Classifications

• • 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 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 includes a 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 avoid a rise in 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 cap for a piloted ammunition comprising a cylindrical ammunition body of longitudinal axis ZZ 'having a front end of an ammunition body. having a central portion to be directed towards a target.
• the cap comprises n portions of cap C1, C2, ... Ci, ... Cn of the same shapes, distributed around said longitudinal axis ZZ ', intended to cover the front end of the ammunition body, n being an integer equal to or greater than 2 where i is the rank of the cap portion, a cap portion Ci having at least one edge in contact, with an edge of a cap portion contiguous thereto in a respective joint plane of two contiguous portions of the cap passing through the longitudinal axis ZZ ', a pyrotechnic device per portion of the cap, each of the pyrotechnic devices comprising, along a longitudinal axis AA', a pyrotechnic pyrotechnic body integral with the respective cap portion Ci, a pusher piston being able to slide sealingly at one of its ends, along said longitudinal axis AA ', the other free end of the pusher piston being in contact with the contiguous cap portion to separate, during the simultaneous activation of the n artifi these pyrotechnics, the edges
• each pyrotechnic device comprises an igniter between the pyrotechnic body and the pusher piston to separate during its activation the pusher piston of the body of the pyrotechnic device and exert a separating force F between the two contiguous cap portions.
• the cap comprises two cap portions of symmetrical shapes with respect to an assembly plane passing through the longitudinal axis ZZ ', the two cap portions being a lower half-cap and an upper half-cap.
• the two assembled half-caps intended to closely encompass the front end of the munition body each comprise an outer surface wall in the form of a half-ovoid of axis of revolution ZZ 'forming the outer surface of the front of the ammunition.
• the two assembled half-caps comprise an inner surface of ovoid shape covering the central part of the munition body connected to another inner surface of circular cylindrical shape comprising a thread intended for the realization of a thread connection. with the ammunition body, a circular edge to abut on a shoulder of the ammunition body when screwing on the ammunition body.
• the two half-caps comprise in the thickness of their wall, at the other inner surface of circular cylindrical shape, cells on either side of a plane Py perpendicular to the plane of assembly passing through the axis ZZ 'for the insertion of pyrotechnic devices.
• the pyrotechnic fireworks body further includes an electrical connection pin for receiving at least two electrical wires for activation of the igniter.
• the pyrotechnic devices are mounted head to tail on either side of a plane PY perpendicular to the plane of assembly of the two half-caps and passing through the axis ZZ '.
• the lower and upper half-caps each comprise a respective edge in contact with each other in the assembly plane.
• the lower half-cap comprises, on its edge located in the assembly plane, a longitudinal groove extending on either side of the axis ZZ ', the upper half-cap comprising, symmetrically with respect to said assembly plane, on its edge situated in said assembly plane a longitudinal tenon extending on either side of the axis ZZ 'of same external dimensions as those of the longitudinal groove to form an interlocking between the two half-caps type tenon / mortise.
• the two half-caps are held together by a circular cylindrical maintenance belt ZZ 'axis, in a circular groove around two half-caps.
• the holding belt comprises in the assembly plane, on either side of the plane PY, weakening zones to cause the rupture of said holding belt when the half-caps are moved apart by the action of pyrotechnic devices.
• the central portion of the ammunition body of cylindrical shape along the axis ZZ ' is connected to the ammunition body by a circular cylindrical body of the same axis ZZ' having a thread body for tightening by screwing the cap on the ammunition body and a rear part of the munition body comprising a crown-shaped shoulder of axis ZZ 'frustoconical surface inscribed in a generator cone Pe close to a perpendicular on the outer surface of the munition body, at said shoulder, the cap having an inner surface of ovoid shape covering the central portion of the munition body connected to another inner surface of circular cylindrical shape having another thread of the same diameter as the threading of bodies for making a threaded connection between the cap and the ammunition body, a circular edge of the same shape as the shoulder of the ammunition body abuts on this shoulder during screwing of the cap on the ammunition body.
• the shoulder comprises a crown-shaped groove ZZ 'open on its frustoconical surface containing an electrical insulating material comprising on said frustoconical surface two annular tracks, made of electrically conductive material, axes of revolution coinciding with the axis ZZ 'for the electrical connection of pyrotechnic devices.
• the pyrotechnic pyrotechnic body further comprises an electrical connection pin intended to receive at least two electrical wires each equipped with a flexible contact in contact with a respective annular track in the shoulder. of 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 munition equipped with an ejectable protective cap according to the invention
• Figure 1c shows a detail of the sectional view of Figure 1a showing the power supply paths of the pyrotechnic devices of the cap;
• FIG. 3a shows a front view of the munition of FIG. 1a equipped with its ejectable cap
• FIG. 3b shows a detail view of Figure 3a around the weakening zone of a belt holding the cap
• - Figure 4 shows a partial view at one of the pyrotechnic devices during the separation of the edges of the half-caps
• FIG. 7 shows a front view of an ejection cap according to the invention made from three portions C1, C2, C3 contiguous and cap;
• FIG. 1a shows a partial view in axial section of the front end of a piloted munition equipped with an ejectable protective cap according to the invention.
• the central portion 14 of the ammunition body of cylindrical shape along the axis ZZ ' is connected to the munition body 10 by a circular cylindrical body 26 of the same axis ZZ' having a body thread 28 for tightening by screwing the cap on the ammunition body 10 and a rear portion 24 of ammunition body having a shoulder 30 in the form of a crown of axis ZZ 'frustoconical surface inscribed in a generator cone Pe close to a perpendicular to the outer surface of the ammunition body at said shoulder 30.
• the cap has a circular edge 48 of the same shape as the shoulder 30 of the munition body 10 to abut on this shoulder 30 during screwing of the cap on the ammunition body 10.
• the two half-caps C1, C2 comprise in the thickness of their wall, at the other surface 42 of circular cylindrical shape, cells 50, 52 on either side of the assembly plane for insertion. pyrotechnic devices 20, 22.
• FIG. 2a shows a cross-sectional view showing the pyrotechnic devices of the piloted munition of FIG. 1a.
• FIG. 2b is a partial cross-sectional view of one of the pyrotechnic devices of the piloted munition of FIG. 1a.
• FIGS. 2a and 2b show in this embodiment of the igniter type.
• FIG. 2b shows in particular a sectional view of the right pyrotechnic device 20 along a plane Pz perpendicular to the axis ZZ 'passing through the longitudinal axes AA' of the right and left pyrotechnic devices 20 and 22.
• Each pyrotechnic device comprises, along its longitudinal axis
• a pyrotechnic pyrotechnic body 60 a pyrotechnic pyrotechnic body 60 and a pusher piston 62 slidably sealing on the pyrotechnic body 60 along the longitudinal axis AA'.
• the pyrotechnic body 60 comprises on the side of the pusher piston 62 a cylindrical sleeve 64 having a cavity 65 and in this cavity 65 an igniter 66 for releasing gases under pressure in the cavity 65.
• the pusher piston 62 comprises, at one of its two ends, on the side of the pyrotechnic pyrotechnic body 60, a cylindrical wall 68 that can slide sealingly on the cylindrical sleeve 64 of the pyrotechnic device and, at its other free end, a wall 69 for closing the pusher piston to form a chamber 70 between the pusher piston 62 and the cylindrical sleeve 64.
• the cylindrical sleeve 64 has a passage 72 in the axis AA 'for the passage of the gases produced by the igniter 66 towards the chamber 70 formed between the pusher piston 62 and the cylindrical sleeve 64.
• the cylindrical sleeve 64 has a seal 80 on its periphery in a plane perpendicular to the longitudinal axis AA ', in contact with an inner surface of the cylindrical wall 68 to obtain the piston piston / cylindrical sleeve sealing.
• Electronics embedded in the ammunition ensures the sending of electrical pulses on the annular tracks a1, a2, transmitted by the electrical son 92 and the electrical connection pin 90, to activate the igniters 66 pyrotechnic devices.
• pyrotechnic devices 20, 22 are mounted head to tail on both sides of the plane PY in the respective cells 50, 52 opening at the level of plane P1, according to the axes AA 'of the pyrotechnic devices and on both sides of said assembly plane P1
• the body of the right pyrotechnic device 20 is integral in its cell 50 with the lower half-cap C1
• its pusher piston 62 is then integral in translation with the upper half-cap C2
• the body of the left pyrotechnic device 22 being secured in its cell 52 of the upper half-cap 22, its pusher piston 62 is then integral in translation with the lower half-cap C1.
• FIG. 3a shows a front view of the ammunition of FIG. 1a equipped with its ejection cap.
• the lower half-caps C1 and upper C2 each comprise a respective edge 100, 102 in contact with each other in the plane P1 closing the ejection cap of the ammunition.
• the two half-caps are assembled to one another by an interlocking type tenon / mortise.
• the lower half-cap C1 comprises, on its edge 100 located in the assembly plane P1, a longitudinal groove 1 10 extending on either side of the axis ZZ '.
• the half upper cap C2 comprises, symmetrically with respect to the assembly plane P1, on its edge 102 located in said assembly plane P1 a longitudinal tenon 1 12 extending on either side of the axis ZZ 'of the same outer dimensions than those of the longitudinal groove 100 to form the interlocking type mortise / mortise (see Figures 1a and 1b).
• This type of interlocking ensures, in addition, a perfect hermeticity of the cap.
• the two half-caps C1, C2 are held together to form the cap according to the invention by a holding belt 120 around the cap at the other inner surface 42 of circular cylindrical shape of the cap.
• the half-caps comprise a circular groove 130, of identical dimensions to those of the holding belt, around the axis ZZ '.
• the holding belt 120, inserted in the circular groove 130, is bonded to the two half-caps by gluing.
• the two half-caps thus connected by the holding belt are made integral with the munition body by the threaded connection (threads 28, 44).
• the holding belt 120 has in the assembly plane P1 on either side of the plane PY embrittlement zones 140 to achieve its rupture when the spacing of the half-caps by the action of pyrotechnic devices.
• Figure 3b shows a detail view of Figure 3a around the weakening zone of the belt holding the cap.
• the optics of the ammunition homing device at the front of the ammunition body, is protected by the ejection cap.
• an electrical pulse is sent by an electronics embedded in the munition to the two pyrotechnic devices 20, 22 via the two annular tracks a1, a2 and the flexible contacts 11, 12 of the electrical wires 92 pyrotechnic devices (see Figure 2).
• This electrical impulse initiates simultaneously the igniters 66 of the two pyrotechnic devices positioned head to tail in the half-caps as shown in Figure 2a.
• the igniters 66 then generate gases under a pressure in the cavity 65 of the respective cylindrical bushings 64.
• the gases come under pressure through the passages 72 in the chambers 70 of the two pyrotechnic devices 20, 22.
• the pressure of the gases tends to increase the volume of the chambers 70 (height D of the chamber) very rapidly moving the pusher piston 62 away from the body 60 of the pyrotechnic device.
• the piston and the body of the pyrotechnic devices being secured respectively to the one and the other half-cap produce forces F of separation of the two half-caps until the rupture, at the weakening zones 140, of the belt 120.
• Figure 4 shows a partial view at one of the pyrotechnic devices during the separation of the edges of the half-caps.
• the two half-caps being no longer held by the holding belt 120 are ejected on the sides of the ammunition perpendicular to the axis of the ammunition.
• 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 plane P1 appearing by the spacing of the edges 100, 102 of the two half-caps which facilitates their ejection.
• the ammunition finds an aerodynamic profile very close to its initial profile before ejection.
• the direction of the threading 28, 44 will be oriented in a preferred direction, that is to say that the angular acceleration of the ammunition will be exerted in the direction which favors the tightening the cap on the ammunition body.
• FIG. 8 shows another exemplary embodiment of the ejection cap according to the invention comprising four identical contiguous cap portions C1, C2, C3, C4 assembled according to 90-degree assembly planes P1, P2.
• a major advantage of the ejection cap according to the invention is that it incorporates its own pyrotechnic ejection system, essentially the pyrotechnic devices.
• the cap with its pyrotechnic ejection system are independent of the ammunition.
• the integration of the cap with the ammunition is performed at the last moment, when using the ammunition, which gives it an extra security aspect

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Chemical & Material Sciences (AREA)
• Aviation & Aerospace Engineering (AREA)
• Combustion & Propulsion (AREA)
• Automotive Seat Belt Assembly (AREA)
• Clamps And Clips (AREA)

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• 2010
  • 2010-10-29 FR FR1004270A patent/FR2966920B1/fr active Active
• 2011
  • 2011-10-25 EP EP11776412.6A patent/EP2633262A1/de not_active Withdrawn
  • 2011-10-25 US US13/882,374 patent/US20140145024A1/en not_active Abandoned
  • 2011-10-25 WO PCT/EP2011/068690 patent/WO2012055889A1/fr not_active Ceased

Non-Patent Citations (1)

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