Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
  • B64C1/38—Constructions adapted to reduce effects of aerodynamic or other external heating
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B10/00—Means for influencing, e.g. improving, the aerodynamic properties of projectiles or missiles; Arrangements on projectiles or missiles for stabilising, steering, range-reducing, range-increasing or fall-retarding
  • F42B10/32—Range-reducing or range-increasing arrangements; Fall-retarding means
  • F42B10/38—Range-increasing arrangements
  • F42B10/42—Streamlined projectiles
  • F42B10/46—Streamlined nose cones; Windshields; Radomes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B15/00—Self-propelled projectiles or missiles, e.g. rockets; Guided missiles
  • F42B15/36—Means for interconnecting rocket-motor and body section; Multi-stage connectors; Disconnecting means

Definitions

• the invention relates to the protective caps of the homing device of the guided munitions and more particularly to ammunition whose length is limited.
• Guided or piloted munitions such as those of the rocket or projectile or missile type, are equipped with optical and electronic guidance systems to ensure, after a flight phase followed by a target approach phase, high reliability and reliability. impact accuracy of the ammunition on the target.
• the piloting of certain types of missiles or guided rockets is done using a laser beam.
• An optical missile detects the laser beam illuminating the target and a missile calculator determines the flight parameters to reach the target.
• the guidance optics located at the front end of the missile (nose or missile head), or the ammunition piloted in a general case, that is to say at the end of the ammunition which is directed towards the target comprises a breakable protection cap, on the one hand, to protect the optics of the seeker from impacts by bodies present in the air during the flight phase and, on the other hand, to prevent a rise temperature of the missile control electronics associated with the optics of the homing device by the aerodynamic friction of the head of the munition.
• This cap can thus protect the guiding optics of the ammunition, depending on the case, during a firing phase, for example, when crossing a seal; during a ballistic phase, in the case of a rocket or projectile; during a cruise phase, in the case of missiles.
• an ejection system must be provided to release the emerging optics of the homing device.
• Ejectable protective caps of the state of the art protecting the optics of the homing devices are not suitable for ammunition of limited length because of their large sizes.
• the invention proposes an ejectable protective ejection cap for a piloted ammunition comprising a munition body (10) of cylindrical shape with a longitudinal axis ZZ 'having a front end.
• Ammunition body (12) having a central portion (14) to be directed towards a target, the cap having n portions of the cap C1, C2, ... Ci, ...
• n an integer equal to or greater than 2
• i being the row of the cap portion
• a cap portion Ci having at least one edge (90, 92) in contact with an edge of a cap portion contiguous thereto in a respective joint plane (P1, P2, P3) of two contiguous cap portions passing through the longitudinal axis ZZ '
• a pyrotechnic device (30, 32) per cap portion (C1, C2, C3, C4), c each of the pyrotechnic devices comprising, along a longitudinal axis AA ', a pyrotechnic pyrotechnic body (40) integral in translation with the ammunition body (10), a pusher piston (42) being able to slide in leaktight manner at one of its ends, along the longitudinal axis AA ', on the pyrotechnic body (40), the free end of the pusher piston being in contact with the respective cap portion (
• the cap has an ovoid portion at the front end (12) of the ammunition body (10) extending rearward of said ammunition body by a frustoconical portion (104) of longitudinal axis ZZ 'having a circular edge (106) about said axis ZZ 'and, in the zone of connection between the ovoid portion and the frustoconical portion, weakening grooves of circular shapes around the longitudinal axis ZZ', an external weakening groove (1 10 ) on the side of its outer surface and an inner weakening groove (1 12) on the side of its inner surface.
• the cap portions are half-caps, one lower half-cap and an upper half-cap of symmetrical shapes with respect to the assembly plane.
• each cap portion is in contact with the pusher piston of a respective pyrotechnic device via a resuming finger integral with the cap portion.
• each pyrotechnic device comprises an igniter between the pyrotechnic body and the pusher piston to separate during its activation the pusher piston of the pyrotechnic body and exert a separating force F on the respective cap portion .
• the other free end of the pusher piston comprises a pusher piston head forming, on the side of the pyrotechnic firework body, a shoulder having a sloped surface intended to be in contact with another surface of the same slope.
• the recovery finger of said cap portion and, at this same other free end of the pusher piston on the side close to the ammunition body a longitudinal groove parallel to the axis AA ', a cylindrical pin integral with one of its ends of the body ammunition being inserted through the other end into the longitudinal groove to limit the stroke of the pusher piston of the pyrotechnic device during activation of the igniter.
• the pyrotechnic fireworks body includes an electrical connection pin for receiving electrical wires for activating the igniter.
• the lower and upper half-caps each comprise a respective edge in contact in the assembly plane, the lower half-cap having on its edge a longitudinal groove extending on either side of the axis.
• ZZ ' the upper half-cap having on its edge, symmetrically with respect to the assembly plane, a longitudinal tenon extending on either side of the axis ZZ 'of the same external dimensions as those of the longitudinal groove to form a socket type mortise / mortise.
• the ejectable breakable cap comprises, surrounding the frustoconical portion, a ring for holding the n portions of the cap on the ammunition body, said retaining ring being retained on the n portions of the cap by gluing, crimping or fitting. .
• the retaining ring comprises, on one side, a tapered edge at the frustoconical portion having the weakening grooves and, on the opposite side, towards the rear of the munition, a circular edge in a plane P4 perpendicular to the longitudinal axis ZZ '.
• the ejectable breakable cap comprises on the side of the frustoconical portion a circular cap edge, the circular cap edge and the circular edge of the retaining ring being abutted, in the same plane P4 against a shoulder, in a plane perpendicular to the longitudinal axis ZZ 'of the munition body.
• the smallest diameter of the frustoconical part of the cap being on the rear side of the munition to create a counter slope for holding the half-caps on the ammunition body
• the ammunition body has a circular zone around the outer surface axis ZZ 'having the same holding slope as the internal surface of the frustoconical portion so as to hold the two half-caps on the ammunition corps.
• a main objective of the invention is the production of small ejectable protective caps for guided munitions of limited length. Another objective is to achieve an aerodynamic cap to retain after ejection of the cap an aerodynamic profile of the ammunition close to its profile before the ejection of the cap.
• FIG. 1a shows a partial view in axial section of the front end of a piloted ammunition equipped with an ejectable protective breakable cap according to the invention
• Figure 1b shows a partial view in axial section perpendicular to the axial section of the front end of the munition of Figure 1a;
• FIG. 2 shows a partial sectional view of one of the pyrotechnic devices of the ammunition of Figures 1a and 1b;
• FIG. 3a shows a cross sectional view of the munition of FIG. 1a:
• FIG. 3b shows a front view of the munition of FIG. 1a equipped with its ejectable breakable cap
• FIG. 4 shows a partial view of the half-caps of FIG. 1b during their separation
• FIG. 5 shows an axial sectional view of the munition of Figure 1b after ejection of the ejectable breakable cap
• FIG. 6 shows a sectional view of one of the pyrotechnic devices of the munition after ejection of the cap;
• FIG. 7 shows a front view of the ammunition after ejection of the cap
• FIG. 8 shows a front view of an ejectable breakable cap according to the invention made from three contiguous portions of the cap and;
• FIG. 1a shows a partial view in axial section of the front end of a piloted ammunition equipped with an ejectable protective breakable cap according to the invention.
• Figure 1b shows a partial view in axial section perpendicular to the axial section of the front end of the munition of Figure 1a.
• the ammunition of FIGS. 1a and 1b comprises a munition body 10 having a front end 12 of said ammunition body 10 covered by the ejectable breakable cap according to the invention.
• a central portion 14 of the ammunition body 10 may comprise, for example, an optics of the ammunition homing device (not shown in the figures).
• the two cap portions are two half-caps, a lower half-cap C1 and an upper half-cap C2 of symmetrical shapes with respect to an assembly plane P1 of the two half-caps passing through the longitudinal axis.
• the ejectable breakable cap comprises on both sides of a plane PY passing through the axis ZZ 'perpendicular to the plane of assembly P1 and equidistant from the axis ZZ', two pyrotechnic devices, of longitudinal axes AA ', integral with the ammunition body 10.
• the pyrotechnic devices are intended to exert, during their activation, separation forces half-caps.
• the ejectable breakable cap comprises a right pyrotechnic device 30 to exert a force F on the lower half-cap C1 and a left pyrotechnic device 32 to exert the same force F but in the opposite direction on the upper half-cap C2 .
• Figure 2 shows a partial sectional view of one of the pyrotechnic devices of the ammunition of Figures 1a and 1b.
• the pyrotechnic devices are in this embodiment of the igniter type.
• FIG. 2 shows in particular a sectional view of the left pyrotechnic device 32 along a plane Pp parallel to the plane Py passing through the longitudinal axis AA 'of action of said left pyrotechnic device.
• Each pyrotechnic device comprises, along its longitudinal axis AA ', a pyrotechnic pyrotechnic body 40 and a pusher piston 42 that can slide sealingly on the pyrotechnic body 40 along the longitudinal axis AA'.
• the pyrotechnic body 40 comprises on the side of the pusher piston 42 a cylindrical sleeve 44 having a cavity 45 and in this cavity 45 an igniter 46 for releasing pressurized gases into the cavity 45.
• the fireworks pyrotechnic 40 comprises an electrical connection pin 50 intended to receive electrical wires 52 for the activation of the igniter 46.
• the cylindrical sleeve 44 further comprises a passage 56 in the axis AA ', for the passage of the gases produced by the igniter 46 to a chamber 58 formed between the pusher piston 42 and the cylindrical sleeve 44.
• the pusher piston 42 has, at one of its two ends on the side of the pyrotechnic body 40, a cylindrical wall 60 that can slide sealingly on the cylindrical sleeve 44 of the pyrotechnic device.
• the cylindrical sleeve 44 has a seal 64 on its periphery in a plane perpendicular to the longitudinal axis AA ', in contact with an inner surface of the cylindrical wall 60 to obtain the piston / cylindrical sleeve sealing.
• the pusher piston 42 has at its other free end a head
• plunger piston forming, on the side of the pyrotechnic pyrotechnic body 40, a shoulder 70 having a surface 72 against slope intended to be in contact with another surface 74 of the same slope of a recovery finger 76 integral with the half-cap respective to the pyrotechnic device considered.
• each half-cap allows, among other things, to angularly position the half-caps C1, C2 on the ammunition body 10.
• the pusher piston head 66 On the side of this same other free end of the pusher piston 42, close to the munition body 10, the pusher piston head 66 has a longitudinal groove 80 parallel to the longitudinal axis AA '.
• a cylindrical pin 82 secured by one of its ends to the ammunition body 10 is inserted by its other end into the longitudinal groove 80 to limit the stroke of the pusher piston 42 during the activation of the igniter 46 of the pyrotechnic device.
• the pyrotechnic device 30, 32 being mounted on the ammunition body, the head 66 of the pusher piston comprises a hole 84 of axis CC perpendicular to the axis AA 'opening into the groove 80 for the insertion of the pin 82 into the ammunition corps 10.
• Figure 3a shows a cross sectional view of the munition of Figure 1a.
• the transverse view of FIG. 3a is a section along a plane normal to the axis ZZ 'passing through the axes AA' of the right and left pyrotechnic devices 32 and 32.
• the pyrotechnic devices 30, 32 are mounted head to tail on both sides of the plane PY.
• the bodies 40 of the pyrotechnic devices are secured to the munition body 10 and locked in translation along their longitudinal axis AA 'in the munition body 10.
• the pusher piston 42 of the left pyrotechnic device 32 is in contact, as previously described, with the upper half-cap C2 via its resetting finger 76.
• the pusher piston 42 of the right pyrotechnic device 30 is in contact with the lower half-cap C1 by means of the resumption finger 76 of said lower half-cap C1.
• FIG. 3b shows a front view of the munition of FIG. 1a equipped with its ejectable breakable cap.
• the lower half-caps C1 and upper C2 each comprise a respective edge 90, 92 in contact with one another in the assembly plane P1 closing the ejectable breakable cap of the munition.
• the lower half-cap C1 has, on its edge 90 located in the assembly plane P1, a longitudinal groove 100 extending on either side of the axis ZZ '.
• the upper half-cap C2 comprises, symmetrically with respect to the assembly plane P1, on its edge 92 located in said assembly plane P1 a longitudinal tenon 102 extending on either side of the axis ZZ ' of the same external dimensions as those of the longitudinal groove 100 to form, when the two half-caps C1, C2 are in contact, a tongue-and-groove type interlock (see FIG.
• the ovoid part of the ejectable breakable cap extends towards the rear of the munition by a frustoconical portion 104 of axis ZZ 'having a circular cap edge 106 around the axis ZZ' of the munition body 10, a half part frustoconical lower 107 for the lower half-cap C1 and an upper frustoconical half-portion 108 for the upper half-cap C2.
• the smallest diameter of the frustoconical portion of the cap is directed towards the rear of the ammunition to create a counter slope for holding the breakable cap ejectable on the ammunition body 10.
• the ammunition body 10 comprises a circular zone 109 around the outer surface axis ZZ 'having the same holding slope as the inner surface of the frustoconical portion 104 of the breakable cap ejectable so as to maintain the ejectable breakable cap (or both half-caps ) on the ammunition body 10.
• the zone of connection between the ovoid part and the frustoconical part of the ejectable breakable cap comprises embrittlement grooves around the circumferentially shaped cap ZZ ', an external weakening groove 1 10 on the outer surface of the cap and an internal weakening groove 1 12 on the inner surface of the ejectable breakable cap.
• the two half-caps are held on the munition body 10 by a retaining ring 120 surrounding the frustoconical portion.
• the retaining ring 120 comprises, on one side, a tapered edge at the frustoconical portion 104 having the embrittlement grooves 1 10, 1 12 of the cap and, on the opposite side towards the rear of the ammunition, an edge circular ring 122 in a plane P4 perpendicular to the axis ZZ '.
• the circular edge 106 of the cap and the circular edge 122 of the retaining ring 120 are in abutment, in the same plane P4 against a shoulder 130, in a plane perpendicular to the longitudinal axis ZZ ', of the munition body 10.
• the retaining ring 120 can be fixed on the frustoconical portion 104 of the cap by gluing. Similarly, the frustoconical portion of the cap may also be bonded to the circular zone 109 of the ammunition body to provide greater rigidity and securing safety of the breakable cap ejectable on the munition.
• the optics of the ammunition seeker at the front of the ammunition body is protected by the ejectable breakable cap.
• an electrical pulse is sent by an electronics embedded in the munition to the two pyrotechnic devices 30, 32 via the power supply son 52 (see Figure 2). This electrical pulse simultaneously initiates the igniters 46 of the two pyrotechnic devices 30, 32 positioned head to tail as shown in Figure 3a.
• the igniters 46 then generate pressurized gases in the cavity 45 of the respective cylindrical bushings 44.
• the igniters can be reinforced by a complementary charge.
• the gases arrive under pressure through the passages 56 in the chambers 58 of the two pyrotechnic devices 30, 32.
• the pressure of the gases tends to increase the volume of the chambers 58 (height D of the chamber) very rapidly moving the push piston 42 away from the body pyrotechnic device 40 and therefore producing the spacing of the two half-caps of the assembly plane P1 by a respective force F in the axis AA 'of the pusher piston.
• the two plunger piston are held at the end of stroke by the respective pins 82 abutting on the lower edge of the grooves 80 in the head of the plunger pistons which prevents any ejection of metal components that can strike the munition.
• the piston heads are positioned at the end of the race at the outer profile of the ammunition to obtain a new harmonious aerodynamic profile.
• the pressure of the gases is maintained in the chamber 58 of the pyrotechnic devices through the seal 64, the plunger pistons 42 thus remaining locked in their end position.
• Figure 4 shows a partial view of the half caps of Figure 1b during their separation.
• the two pusher piston heads 66 are supported on the respective fingers 76 of the lower half-caps C1 and upper C2 which apart break up at their embrittlement grooves 1 10, 1 12.
• the ring 120 of maintenance retains the frustoconical portion 104 of the two half-caps on the ammunition body 10.
• Figure 5 shows an axial sectional view of the munition of Figure 1b after ejection of the ejectable breakable cap.
• the slope of the surface 72 of the pusher piston head and that of the other surface of the finger 76 for the recovery of the half-caps have the role of ensuring, during the ejection phase of the two half-caps, the correct hooking between the heads 66 of push pistons and the fingers of recovery 76 of the half-caps.
• Figure 6 shows a sectional view of one of the pyrotechnic devices of the munition after ejection of the cap.
• the chamber takes its height H maximum when the pin 82 is in abutment in the groove 80.
• the spacing of the two half-caps by the pyrotechnic devices also allows the air at high speed to rush into the opening in the assembly plane P1 appearing by the separation of the edges 90, 92 of the two half-caps facilitating their ejection.
• the components generated by the centrifugal force also participate in the ejection of the two half-caps.
• the ammunition finds an aerodynamic profile very close to its initial profile before ejection, which in no way disturbs the piloting guidance laws of the ammunition, hence a precision of firing unaltered by the removal of the cap according to the invention.
• Figure 7 shows a front view of the ammunition after ejection of the two half-caps.
• the ejectable breakable coping of small dimensions makes it possible to protect the optics of the homodirector of the guided munition up to the ejection of the cap portions but also during the storage, logistics and other operational phases. (tactical).
• the two half-caps may be identical or interconnected by a flexible and foldable area thus making it possible to produce in one piece the two half-caps, for example by plastic injection.
• FIG. 9 shows another exemplary embodiment of the ejectable breakable cap according to the invention comprising four identical contiguous cap portions C1, C2, C3, C4 assembled according to 90-degree assembly planes P1, P2.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Aviation & Aerospace Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Automotive Seat Belt Assembly (AREA)
• Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)

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• 2010
  • 2010-10-29 FR FR1004269A patent/FR2966919B1/fr active Active
• 2011
  • 2011-10-25 EP EP11775941.5A patent/EP2633261A1/de not_active Withdrawn
  • 2011-10-25 WO PCT/EP2011/068688 patent/WO2012059369A1/fr not_active Ceased
  • 2011-10-25 US US13/882,398 patent/US20130264425A1/en not_active Abandoned
• 2013
  • 2013-04-28 IL IL226021A patent/IL226021A0/en unknown

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