FR2610397A1 - TEMPORARY BREAKER WITH ALL AZIMUT PERCUSSION FOR AMMUNITION FIRED BY A WEAPON, IN PARTICULAR A GRENADE - Google Patents

Abstract

The fuse comprises: - a pyrotechnic chain (201-205) put into the chain alignment position by centrifugal effect during the firing of the ammunition, - a percussion system (300) with a striker (301), a supporting member, first spring means (303), trigger means for releasing the striker and locking means, - a delay assembly (400) comprising a volume (404) of microballs which is progressively discharged under the action of a follower piston (401) and of second spring means (408). According to the invention, the trigger means comprise an annular element divided into a plurality of sectors (307), each of these sectors interacting with the supporting member of the striker by means of a ramp-shaped face (312), with at least one retaining ball (304) being interposed. This ensures not only conventional percussion by a front shock, but also percussion by a lateral effect under a high-incidence shock or the self-destruction of the ammunition.

Description

The present invention relates to a timing rocket for

  ammunition fired by a weapon, including a grenade.

  At the moment of its arrival on the target or on the ground, the grenade is subjected to impact characteristics which can be extremely variable: frontal impact on hard target, on soft target, impact with non-zero incidence, even able to

until a side impact, ...

  It is therefore desirable that the initiation of the charge can be performed in all circumstances, regardless of the ballistic characteristics of the trajectory and the nature or

  impact incidence ("all-out" percussion).

  In addition, it is important to be able to self-destruct the grenade in the event of an incident.

  trajectory, for safety reasons.

  Finally, a delay is essential to ensure

mouth safety.

  The present invention proposes a timing rocket

  allowing precisely to meet all these conditions.

  The rocket of the invention is of the general type comprising, housed in a rocket body: a pyrotechnic ignition and firing system, comprising a first set composed of a concutating primer and a detonation relay housed in a moving assembly and a second assembly consisting of a transmission relay, the moving equipment preventing the transmission of fire between the two sets in storage configuration of the fuse, and being placed in the chain alignment position, corresponding to an arming configuration, by centrifugal effect when firing the ammunition, - a percussion system of the primer comprising a firing pin carried by a support member connected to the body of the fuze, first spring means for tensioning the firing pin away from the primer, triggering means for releasing the striker energized and allow the impact thereof on the primer, and the locking means of the percussion system in storage configuration, - a timer assembly comprising a flowable volume, in particular a volume of microbeads, progressively evacuated during the transition from the storage configuration to the cocking configuration under the action of a delivery piston, solicited by second means resso.-t and released by centrifugal effect when firing the ammunition. In a manner that is characteristic of the invention, the triggering means comprise an annular element divided into a plurality of peripherally spaced sectors, each of these sectors cooperating with the striker support member via a ramp-shaped face with interposition of at least a retaining ball placed in respective homologous housings of the annular sector, a connecting element to the body of the fuse and the support member, the latter being interposed between the annular sector and the connecting element, so as to maintain in place each sector as long as the normal ramp component of the centrifugal force sustained by the sector remains greater than the normal ramp component,

  of the force exerted by the first spring means.

  In this way, the striker is released during a side effect percussion resulting from a high impact impact, or when the centrifugal effect undergone by the rocket becomes less than a threshold, related to the force exerted by the first means spring, to operate the self-destruction of the ammunition

in case of ballistic failure.

  Preferably, the rocket of the invention also has the following advantageous characteristics: the front face of the firing pin is placed opposite the frontal region of the casing body of the rocket, so as to allow the direct percussion of the primer by crushing the envelope resulting from an impact with little or no incidence; the mobile equipment carrying the primer is axially movable in the frontal direction, so as to allow direct percussion of the primer by projection thereof against the striker, in the event of impact at low or zero incidence without sufficient crushing the front part of the envelope; - Third spring means are also provided for prestressing the sectors of the annular element so as to spread them radially, the force exerted by these third spring means being added to that resulting from the centrifugal force experienced by the sectors. ; the connecting element of the firing pin to the body of the fuze is integral with the delivery piston of the microbeads, and the moving equipment comprises a projection housing of the firing pin tip, so that the latter is not placed in the position of arming after complete evacuation of the volume of microbeads; - The presence of the striker tip in the corresponding housing of the mobile unit immobilizes the latter in rotation and locks in misalignment position chain, so as to prevent any alignment of the pyrotechnic chain before the complete evacuation of the volume of microbeads.

  Other features and advantages of the invention.

  will appear on reading the detailed description

  BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational section showing the internal structure of the rocket of the invention, FIG. 2 is a partial section, FIG. also in elevation, similar to FIG. 1; FIG. 3 is a half-section along the line III-II of FIG. 2; FIG. 4 shows the rocket just after the start of the blow; FIG. rocket during the delay phase, - figure 6 shows the rocket in its cocking configuration, after completion of the delay phase, - figure 7 illustrates the percussion phase, in the case of a low intensity frontal impact FIG. 8 illustrates the percussion phase, in the case of a high impact side impact, or in the case

self-destruction of the ammunition.

  In the figures, the reference 100 generally designates the body of the rocket, intended to be placed for example on a grenade intended to be fired by a weapon, the rocket coming to screw on the orifice of the grenade through a part threaded 101 formed at its base, the axis of the body of the rocket being referenced 110. All parts of the rocket is supported by a single element 102 of injected plastic material, closed by a shell 103 forming a protective envelope and

  providing the rocket with the necessary aerodynamics.

  The one-piece element 102 in particular supports the pyrotechnic ignition and firing chain 200, which comprises a concutant primer 201, a detonation relay 202 and a transmission relay 203. The primer 201 and the detonation relay 202 communicate via a fire transmission channel 204, the assembly being carried by a mobile assembly 205 which, in the storage configuration shown in FIG. 1, ensures both the misalignment of the primer 201 with respect to the striker 301 and that detonation relay 202 relative to the transmission relay 203, the latter being crimped permanently in a cylindrical extension 104 of the body of the

rocket, coaxial with axis 110.

  The moving element 205 is rotatable according to a degree of freedom, around an axis 220 transverse to the axis 110, by means of two journals 206 enabling it to be journalled in the notches 105 of a part 106 of the body of rocket forming caliper to support the crew. The notches 105, whose width is complementary to the diameter of the journals 206, extend parallel to the axis 110 and open on the front of the

part 106 of the rocket body.

  The crew 205 is movable in axial translation, the journals 206 being able to move axially in the notches 105, but it is initially maintained in the rear position by means of return springs 208: this additional degree of freedom in axial translation is intended in fact to allow the projection of the crew carrying the primer 201 against the striker in the event of a frontal impact, as it is

  will describe further with reference to Figure 7.

  An unbalance peg 209, carried by the moving element 205, will allow the alignment of the pyrotechnic chain by centrifugal effect, and a stop 210 will limit the resulting rotation.

  at the position ensuring exactly the chain alignment.

  Finally, it is provided in the mobile assembly 205 a housing 211 initially receiving the striker 301, which has the function of protecting the latter and of immobilizing the mobile eruipage in storage configuration. , as long as the striker will not be removed by displacement in the frontal direction, this displacement corresponding to the passage of the rocket armament configuration. The axes of the housing 211 and the channel 204 intersect the axes 110 and 220. The housing 211 intersects the channel 204 without intersecting the primer 201 or the detonation relay 202. The rocket also comprises a percussion system of the primer, generally designated by the reference 300, with a striker 301 metal, for example brass, set coaxially with the axis 110 in a support member 302 on which is exerted the tension of an axial spring 303 or spring auto -destruction, placed between the top of the cap 103 and the support member 302. In the storage configuration shown in Figure 1, this spring is not compressed; he can

  however, be slightly prestressed.

  The striker is locked to an element 401 by means of balls 304 each inserted into a housing 305 of a front portion 306, of generally cylindrical shape, of the support member 302 of the striker. For example, two diametrically opposed balls are provided, which are also housed in respective cells 402 of the element 401 (or in an annular groove of this element) to ensure the connection between this element.

  last element and the support member 302.

  The balls are maintained by means of an inner annular ring 307, divided into a plurality of sectors, for example two half-sectors in the case of two balls, as illustrated in the figures (the gap between these two halves). sectors is particularly visible figure 8, where it carries

  reference 308). These sectors are prestressed.

  radially outward direction by means of an elastic ring 309 placed in an inner groove adapted to receive it. Finally, the annular sectors 307 are provided with a peripheral groove 310 (apparent in particular FIG. 8), of shallow depth, to prevent slipping

  balls on the outer face of the annular sectors.

  The annular sectors 307 cooperate with the cylindrical portion 306 of the support member 302 by homologous faces in the form of ramps 311 and 312: the ramp 311 formed on the portion 306 is frustoconical and diverges towards the front of the rocket; the ramp 312 formed on the annular sectors 307

has the same taper.

  These ramps, because of their inclination, will make it possible to transform the axial force exerted by the percussion spring 303 into a radial component, which will be combined with the centrifugal force experienced by the annular sectors 307 in the manner

indicated below.

  Finally, the striker proper 301 comprises a front face 313 capable of pushing it towards the starter under the effect of a contact exerted by a boss 107 in the front part of the cap, this bringing into contact resulting from a crushing of the cap after an impact

  frontal incidence low or no, and low intensity.

  In addition, these elements 107 and 313 make it possible to guide the

  axial self-destruct spring 303.

  The rocket of the invention finally comprises a timer system delaying by a few milliseconds the transition to the weapon configuration after firing the projectile provided.

rocket.

  These timing means comprise a fixed cylindrical element 403, locked in place by projections 108 and 109 of the body of the rocket, and receiving the element 401 forming a piston (supporting, as indicated above, the percussion assembly), which is formed of a sleeve coaxial with the axis 110 and which can slide axially inside the

cylinder 403.

  The space between the cylinder 403 and the mobile piston 401 defines an annular chamber 404, of variable volume in

  depending on the position of the piston 401.

  In the storage configuration, the piston is in the rear position, and the volume 404 is filled with a flowable material, preferably glass microbeads -but it may also contain sand, a solid material

  powder, a viscous fluid (oil) or not (water), ...

  The volume of microbeads may flow through a radial orifice 405 formed in the outer cylinder 403 and possibly calibrated according to the equivalent viscosity of the volume of microbeads. In the storage configuration, this orifice 405 is closed by a cylindrical ring 406 or arming ring, immobilized by shear pins 409, calibrated. At the moment of the start of the stroke and after shearing the pins 409, the cocking ring 406 can be erased aft, thus releasing the flow orifice 405; thereafter, the ring 406 will be prevented from returning to the front thanks to a prestressed anti-return ring 407 which

  will abut against the front face of the cock ring.

  To force the flow of the glass microbeads, there is provided a spring 408 or cocking spring, compressed between the base 102 of the body of the rocket and the lower part of the

piston 401.

  In this way, as soon as the orifice 4C5 has been released by erasing the annular ring 406, the piston 401 will slide progressively forward, simultaneously driving

  the entire percussion system that it supports.

  We will now describe the operation of the rocket

the invention.

  Firstly, in the storage configuration (configuration illustrated in FIGS. 1 to 3), the cocking ring 406, immobilized on the cylinder 403 by its shear pins 409, closes the flow orifices 405 of the glass microbeads,

  and the piston 401 is thus prevented from moving.

  The support member 302 of the striker is secured to the piston 401 by the action of the annular sectors 307 subjected to the action of the elastic ring 309, which pushes the balls 304 into the annular groove 402 machined in the piston 401. The spring of self-destruction 303, slightly prestressed, maintains

all in the rear position.

  The point 301 of the firing pin, housed in the orifice 211 of the moving element 205, immobilizes the latter in the misalignment position of the pyrotechnic chain (primary and secondary explosives). At the start of the stroke, during the ballistic phase of acceleration in the barrel of the weapon (FIG. 4), the cocking ring 406 shears the pins 409 by an inertia effect and slides along the cylinder 403; the 407 anti-return ring

  comes immobilize it in the rear position.

  The flow orifices 405 of the glass microbeads are then disengaged and these, urged by the action of the cocking spring 408 as well as by the centrifugal force,

  begin to flow through the orifices 405 (FIG. 5).

  During this so-called timing phase, the assembly formed by the striker 301, its support member 302 and its locking elements is driven by the piston 401 and begins to move forward while compressing the spring of 303. As long as the flow is not completed, the point 301 of the firing pin, still engaged in the orifice 211, blocks the moving assembly 205 in rotation,

  thus ensuring mouth safety.

  Once the microbeads have been completely discharged (FIG. 6), the cocking spring 408 immobilizes the piston 401 in the forward position, the self-destruct spring 303 then being compressed.

at its maximum.

  Under the effect of the centrifugal force, the striker assembly 301-support member 302-locking means 304 is always integral with the piston 401, since the force exerted on the balls 304 by the annular sectors 307 and the elastic ring 309 remains greater than that resulting from the compression of the spring

self-destruct 303.

  Simultaneously, the moving element 205 is released in rotation by the complete erasure of the tip of the striker 301, and unbalanced by the unbalance pin 209 which, under the action of the centrifugal force, aligns the pyrotechnic chain (striker 301, concutant primer 201, fire transmission channel 204,

  detonation relay 202 and transmission relay 203).

  We will now describe how the percussion takes place, it can be performed in three different modes. In a first percussion mode, corresponding to a frontal impact with little or no incidence (FIG. 7), the percussion will be carried out directly, in two possible ways: either by the repression of the striker 301 on the concutant primer 201 following the crushing the front portion of the hull 103, the impact being transmitted by the boss 107 to the front portion 313 of the striker (in case of impact on a relatively hard target); or by self-percussion of the crew 205 which, having a sufficient stroke in the axial direction, will project by inertia effect against the tip of the striker during deceleration, as shown in Figure 7 (case of an impact) on a

relatively soft target).

  In a second mode of percussion, the impact takes place under a high incidence (situation illustrated in figure 8). In this case, the self-destruction system of the rocket is exploited: under the effect of the side impact and the ramp-shaped profile 312 of the sectors 307, and under the action of the self-destruct spring 303, the balls 304 fade and release.n: the support member 302, after leaving the orifices 3C5. The

  striker 301 can then strike concutant primer 201.

  In a third mode of percussion, corresponding to the self-destruction of the grenade in the event of a ballistic incident, the support member of the striker is released as soon as the resultant normal to the ramps 311,312 of the cumulative centrifugal force and the the force exerted by the elastic ring 309 on the sectors 307 becomes smaller than the normal component at the ramps 311, 312 of the force applied on the support member 302 by the self-destructing spring 303. The release of the balls 304

  is then operated in the same way as before.

26 10397

Claims (4)

  1) An all-out percussion timing rocket for ammunition fired by a weapon, in particular a grenade, comprising, housed in a rocket body (100): a pyrotechnic (200) ignition and firing chain, comprising a first set consisting of a concutting primer (201) and a detonation relay (202) housed in a moving assembly (205), and a second assembly consisting of a transmission relay (203), the moving assembly preventing the transmission of fire between the two sets in storing configuration of the fuse, and being put in the chain alignment position, corresponding to an arming configuration, by centrifugal effect when firing the ammunition, - a system of percussion (300) of the primer, comprising a striker (301) carried by a support member connected to the body of the rocket, first spring means (303) for tensioning the firing pin at a distance from the primer, means for trigger to release the striker put under tension and allow the impact thereof on the primer, and means for locking the percussion system in storage configuration, - a timer assembly (400) comprising a volume (404) capable of flow, in particular a volume of microbeads, progressively evacuated during the transition from the storage configuration to the cocking configuration under the action of a delivery piston (401), biased by second spring means (408) and released by centrifugal effect during firing of the ammunition, characterized in that the triggering means comprise an annular element divided into a plurality of peripherally spaced sectors (307), each of these sectors cooperating with the firing pin support member by a shaped face (312) of a ramp with interposition of at least one retaining ball (304) placed in respective housings hocccues (310, 311, 402) of the annular sector, a member (401) for connecting to the body of the rocket e and the support member, the latter being interposed between the annular sector and the connecting element, so as to maintain in place each sector as the component normal to the ramp, the centrifugal force undergone by the sector remains greater than the component, normal to the ramp, of the force exerted by the first spring means, so that the striker is released only when the centrifugal effect undergone by the rocket becomes lower than a given threshold, thus allowing either the Lateral percussion resulting from a high-impact impact, ie the self-destruction of the ammunition in case of ballistic failure. 2) The rocket of claim 1, wherein the front face (313) of the striker is placed vis-à-vis the frontal region of the casing body (103) of the rocket, so as to allow the direct percussion of the primer by crushing the envelope resulting from an impact impact low or zero.   3) The rocket of claim 2, wherein the mobile element bearing the primer is axially movable in the frontal direction, so as to allow the direct percussion of the primer by projection thereof against the striker, in case of impact with little or no impact without crushing   enough of the front part of the envelope.   4) The rocket of claim 1, wherein it is further provided third spring means (309) for preloading the sectors of the annular element so as to spread radially, the force exerted by these third spring means coming s add to that resulting from the force centrifugal effect on the sectors.   ) The rocket of claim 1, wherein the connecting element of the firing pin to the body of the rocket is integral with the delivery piston of the microbeads, and in which the mobile equipment comprises a housing (211) for projection of the point of the firing pin, so that the latter is placed in the cocking position only after complete evacuation of the volume of microbeads.   6) The rocket of claim 5, wherein the presence of the striker tip in the corresponding housing of the moving element immobilizes the latter in rotation and locks it in the misalignment position of the chain, so as to prevent any alignment of the pyrotechnic chain before complete evacuation of the volume of microbeads.