FR2691799A1 - Chemical self destruct system for sub-munition of carrier shell - Google Patents

Abstract

The self destruct system for the explosive consists of a secondary firing pin (15) mounted inside a housing (5b) in the sliding unit (5) that moves the detonator (6) from its safety position to its armed position in line with the main firing pin. A control device (16) releases the secondary firing pin (15) after a predetermined delay when a corrosive agent (30) attacks the retaining element (25) that holds the sec. firing pin (15) against its seat (28) by an arming spring (26).

Description

 The present invention relates to a munition, in particular a submunition intended to be ejected from a carrier projectile, for example a cargo shell or a rocket head or a bomb of the type comprising an explosive charge and a pyrotechnic initiation chain of the load mounted in an arming safety device, said chain including at least one switch element which is movable between a safety position and a position authorizing the operation of the pyrotechnic chain, and at least one locking member movable between a switch lock position in safety position and switch release position.

 The pyrotechnic chain for initiating the charge of such ammunition generally comprises a main striker and a priming device consisting of a detonator primer carried by a slide movable in translation or in rotation. The slide is movable between a safety position where the detonator primer is misaligned with the explosive charge, and an arming position where the detonator primer is substantially aligned along the axis of the striker and the explosive charge. Such a slide thus constitutes a switch element of the pyrotechnic chain, and it is retained in the safety position by at least one locking member or bolt. This lock makes it possible to handle the ammunition and to place it in the cargo shell safely.

 Concretely, several locks are generally provided to prevent any premature initiation of the charge, these inertia or centrifugal type locks being successively released after the firing of the cargo shell.

 Thus, the pyrotechnic chain is only able to operate once the slider has passed into the arming position, that is to say that once the last safety lock is released. The release of the latter lock occurs most often after the munition is ejected from the cargo shell.

 Then, when the munition comes into contact with the ground or a target, the main striker initiates the military charge by percussion of the detonator primer, in a manner known per se.

 However, in the event of a malfunction of the pyrotechnic chain, the ammunition does not explode on contact with the ground or a target. However, once stabilized on the ground, the ammunition remains dangerous, since any subsequent impact may possibly restore the instantaneous operation of the pyrotechnic chain and lead to the initiation of the charge.

 To overcome this dysfunction, it is known to complete the pyrotechnic chain of such ammunition by a self-destruction system which causes the initiation of the detonator primer with a certain delay which is greater than the flight time in free fall. ammunition before it reaches the ground.

 The self-destruction system is housed inside the slide and it also includes a switch element which is movable between a safety position and a position authorizing the operation of the self-destruction system to cause the initiation of the detonator with a certain delay.

The switch is retained in the safety position by a movable locking member between a position for blocking the switch in the safety position and a position for releasing the switch.

In general, self-destruction systems are of the pyrotechnic, chemical or mechanical type like those described in particular in the documents
US-4,873,927, US-4,998,476, EP-0 205,956 and FR-2,650,662.

In each of these systems, the release of the locking member which authorizes the operation of the self-destruction system is released only when the slider passes into the arming position. In other words, these systems are inoperative in the event of a malfunction at the passage of the slide in the arming position.

 The object of the invention is to design a munition in which at least one switch of the pyrotechnic chain is released when the munition is ejected from the cargo shell, in particular the switch of the self-destruction system. so as to authorize the operation thereof even if the slide is not in the arming position.

 To this end, the invention provides a munition of the aforementioned type and which is characterized in that it also comprises control means for releasing the switch which authorizes the operation of the pyrotechnic chain at the ejection of the ammunition, these control means comprising means for holding the locking member of the switch in its blocking position, these holding means being essentially constituted by a part of an adjacent munition on board the cargo shell.

 According to a first application of the invention, the pyrotechnic chain of the munit ion comprises a main striker and a priming device consisting of a detonator primer carried by a slide movable between a safety position and an arming position, this slider constituting the aforementioned movable element forming a switch, while the locking member constitutes a blocking safety for the bucket grout in the safety position until the munition is ejected from the cargo shell.

 According to another application of the invention, the pyrotechnic chain of the munition comprises a main striker and a priming device constituted by a detonator primer carried by a slide movable between a safety position and an arming position, and a system of self-destruction housed in the slide and comprising an auxiliary striker intended to authorize the operation of the self-destruction system to cause the initiation of the detonator primer with a determined delay after the release of this auxiliary striker, the latter constituting the aforementioned movable element forming a switch, while the locking member constitutes at least one blocking security for the auxiliary striker until the munition is ejected from the cargo shell.

 According to another characteristic of the invention, the locking member comprises at least one finger movable in translation inside a first channel formed by an opening provided in the body of the security system for arming and a radial opening provided in the slide, and a spring which tends to eject the finger outside the first channel.

 According to one embodiment of the invention, the locking member comprises a second finger movable in translation inside a second channel formed in the body of the arming security device, this second channel extending perpendicularly to the aforementioned first channel and partly opening at least in this first channel so that the second finger can immobilize the first finger axially, and a spring which tends to eject the second finger outside the second channel.

 In general, the ammunition is of the type comprising a body which contains the charge, said body being surmounted towards one end by the armament security device, said charge, towards its end opposite to the armament security device, being hollow and coated with a coating which delimits an internal space intended to freely receive the arming security device of said adjacent munition, the fingers of the locking member being intended to come into abutment against the coating of said adjacent ammunition which constitutes the aforementioned means of maintenance.

 In the context of the aforementioned second application where the locking member is associated with the functioning of the system of self-destruction of the submunition, the latter can be of the thermal, pyrotechnic or chemical type for example, and according to an important advantage of the Invention, the operation of the self-destruction system is initialized upon ejection of the submunition and is not subject to the passage of the slide in the arming position.

Other advantages, characteristics and details of the invention will emerge from the explanatory description which follows, made with reference to the attached drawings given solely by way of example and in which - FIG. 1 is a partial perspective view of
two ammunition intended to be loaded into a shell
cargo, - Figure 2 is a schematic partial sectional view
according to line II-II of figure 1 before installation
of the two munitions inside the cargo shell, - Figure 3 is a partial sectional view and diagrammatic
that similar to figure 2, after installation of
two munitions inside the cargo shell, - and Figure 3a is a detail view of Figure 1.

 In FIG. 1, two similar munitions 1a and 1b have been partially illustrated placed substantially one above the other. Each munition la and lb comprises a body 2 in which is housed an explosive charge 3. The body 2 of each munition la and lb is surmounted by an arming security device 5, the body 6 of which is closed by a plate bottom 6a fixed to the body 2 by means not shown.

 The arming security device 5 of the munit ion la comprises a pyrotechnic chain consisting of a main striker 8 and a priming device 10 comprising a detonator primer 11 carried by a slider 12. The slider 12 is movable between a safety position where it keeps the detonator primer 11 away from the striker 8, and an arming position where the primer 11 is substantially opposite the striker 8. The priming device 10 constitutes a switch for the pyrotechnic chain, the load 3 can only be initiated by the striker 8 after the passage of the slide 12 in the cocking position. The striker 8 is mounted along the axis of the munition la, and it is screwed into a nut 13 integral in rotation with the body 6 of the armament security system 5, as described in more detail in US Pat. No. 4,488,488 .

 Referring to Figures 2 and 3, the pyrotechnic chain of the munit ion la is completed by a self-destruction system 15 which is mounted in a housing 12a of the slide 12, and whose function is to initiate the initiation detonator 11 with a certain delay after the ejection of the munition la.

 In the example considered here, the self-destruction system 15 is a thermal generator 16 of the pyrotechnic type for example. The generator 16 comprises a sensitive priming composition 17 and a heat generating composition 18, which are housed in an envelope 19. The thermal generator 16 is initiated by a secondary striker 20 secured to the front face of a piston 21 movable in translation inside the slide 12. The secondary striker 20 is armed by a spring 22 which bears on the one hand, on the rear face of the piston 21 and, on the other hand, on a disc 23 which closes the housing 12a of the slide 12. The secondary striker 20 is retained at a distance from the thermal generator 16, with the spring 22 in the banded state, by a locking member 25.

 The locking member 25 is movable between a position for blocking the secondary striker 20 in the safety position, and a release position for the striker 20, the latter constituting a switch for controlling the operation of the self-destruction system 15.

In the example considered here, the locking member 25 comprises two fingers 26 and 27. The finger 26 is movable in translation inside a first channel formed by an opening 29 provided in the body 6 of the device. arming security 5 and a radial opening 30 provided in the slide 12. The finger 26 mounted in the opening 29 is permanently biased by a spring 31 which is supported, on the one hand, against a shoulder 32a and , on the other hand, against a flange 32b, and which tends to eject it outside of this opening 29 in the direction indicated by the arrow
F1. This finger 26 is immobilized axially by the finger 27, so that it projects radially inside the slider 12 to retain the secondary striker 20 in the safety position, for example by pressing against the front face of the piston 21.

 The finger 27 is movable in translation inside a second channel 33 formed in the body 6 of the arming safety device 5. This channel 33 extends perpendicular to the aforementioned first channel 29, 30, and it opens out at less partially in the opening 29 which forms part of this first channel. More specifically, the finger 26 has an annular peripheral groove 35 which, when the finger 26 is in its position where it maintains the secondary striker 20 in the safety position, is located at the intersection zone between the two channels 29, 30 and 33. Thus, towards its end 27a, the finger 27 can engage in this groove 35 and retain the finger 26. Towards its other end 27b, the finger 27 protrudes outside the second channel 33 to take support on part of the munition 1b, as will be described later. The finger 27 mounted in the channel 33 is permanently biased by a spring 37 which bears on the one hand against a shoulder 38a and on the other hand against a flange 38b, and which tends to eject it outwards according to the direction indicated by the arrow F2.

 Concretely, the two munitions 1a and 1b of FIG. 1 are submunitions intended to be loaded on a cargo shell where, in a manner known per se, a plurality of submunitions are stacked in columns.

 Referring to FIG. 1, such a stack is made possible by the fact that the load 3 is hollow towards its end opposite to the arming security device 5, and coated with a coating 40 which delimits an internal space 41 in which can accommodate the arming security device 5 of another submunition. In addition, the body 2 of each submunit ion comprises, towards its end which supports the armament security device 5, a reduction in external diameter which forms an annular stop 42 and, towards its other end, a cylindrical skirt 43 which extends the body 2 beyond the load 3 and which has an annular radial shoulder 44 forming a stop on its internal wall.

 Thus, the arming security system 5 of the submunition la can be housed in the internal space 41 of the submunition lb, the end of the skirt 43 of the submunition lb coming to bear on the stop 42 of the submunition la, when the two munitions la and lb are stacked one on the other.

 Once the two submunitions la and lb stacked one on the other in the cargo shell (FIG. 3), the free end 27b of the finger 27 of the locking member 25 of the submunition la is resting against the wall of the coating 40 of the submunition 1b, which has the effect of axially immobilizing the finger 27.

 Referring to Figures 1 and 3, the slider 12 is in particular held in the safety position by the main striker 8, the end of which protrudes into an opening 47 of the slider 12. In its safety position, the bucket grout 12 compresses springs 48 which bear against washers 49 for example, crimped onto the body 6 of the arming safety device 5.

 Referring to Figures 1 and 2, it should be noted the presence of an elastic tongue 50 which allows to axially immobilize the finger 27 as the submunition la is not in place in the cargo shell. The tongue 50 results for example from a partial cut made in the bottom plate 6a of the body 6 of the weapon security device. At one end, this tongue 50 is integral with the body 2 of the submunition 1a, and it projects into an opening 51 of the second channel 33 to engage in a groove 52 provided at the periphery of the finger 27, so as to that the tongue 50 naturally takes an inclined position. During the operation of placing submunitions la and lb inside the cargo shell, the arming security device 5 of the submunition la is engaged in the internal space 41 of the submunition lb, so that the stop 44 on the internal wall of the skirt 43 of the body 2 of the submunition lb comes to bear on the free end of the elastic tongue 50 (FIG. 3a), which has for effect of lowering it by gradually disengaging it from the groove 52 of the finger 27. When the end of the skirt 43 of the body 2 of the submunition 1b comes into contact with the stop 42 of the body 2 of the submunition 1a, the finger 27 is released and, under the thrust of its spring 37, its end 27b bears against the coating 40 of the load 3 of the sub-munition lb (FIG. 3).

 After the firing of the cargo shell, the submunitions la and lb will be ejected and separate from each other. Thus, when the submunitions separate and as soon as the end 27b of the finger 27 is no longer in contact with the submunition lb, the finger 27 is automatically ejected under the pressure of the spring 37. The ejection of the finger 27 causes the release of the finger 26 which, in turn, is automatically ejected outwards under the pressure of the spring 31. The secondary striker 20 of the self-destruction system 15 is then released and driven by the piston 21 which is pushed by the spring 22 to perforate the envelope 19 and strike the initiating composition 17 of the thermal generator 16.

 In normal operation, after the ejection of the submunition la, a stabilizing tape for example (not shown) is deployed when the submunition la falls. This stabilizing tape, under the effect of its aerodynamic drag combined with a rotational movement of the submunition la, causes the main striker 8 to be unscrewed partially.

 The main striker 8 then emerges from the opening 47 of the slider 12 which, under the thrust of the springs 48 which are associated with it, is moved in translation towards its arming position where the detonator primer 11 is located opposite the striker main 8.

 The charge initiation pyrotechnic chain 3 is in working order, and during the impact of the submunition la on contact with a target or the ground, the main striker 8 which has suddenly moved by the deceleration movement caused on impact, strikes the detonator initiator 11, which causes the initiation of the charge 3. Under these conditions, the self-destruction system 15 although initialized then produces no effect, the heat released by the thermal generator 16 and which propagates in the body of the slider 12 has not caused a rise in temperature sufficient to cause the initiation of the detonator primer 11 carried by the grout bucket 12 before percussion by the main striker 8.

 On the other hand, in the event of malfunction of the main striker 8 for example, the submunition la is not initiated on impact, and it is then the self-destruction system 15 which initiates the detonator primer 11 with a certain delay after the ejection of the submunition la, the rise in temperature of the slider 12 having become sufficient to cause the initiation of the detonator primer 11. If the slider 12 is in the arming position, the load 3 will be initiated, on the other hand if the slide 12 is not in the arming position, the detonator primer 11 will be destroyed and the submunition will be neutralized without risk of initiation of the charge 3 which is a charge of the secondary type. Thus, the release of the locking member 25 upon ejection of the submunition allows the self-destruction system to operate regardless of the state of the slider 12 which carries the detonator primer 11.

 In the example considered above, the self-destruction system 15 is of the thermal type, but it could as well be of the pyrotechnic or chemical type for example.

 Finally, the locking member 25 can also be applied to a slider 12 having no self-destruction system. I1 then constitutes at least one lock which keeps the bucket grout in the safety position and which is released on ejection of the submunition. This release may not automatically cause the passage of the bucket grout 12 in the cocking position, if another lock is provided which is only released after the ejection of the submunition.

 It is possible to provide a locking member comprising only one finger 26. Provision will then be made for temporary retention of the latter in the locking position against the action of its spring 31, for example a pin. These means will be removed in the workshop when stacking the cluster munitions in a column.

 The embodiment described above and comprising two fingers 26 and 27 and an elastic tongue 50 facilitates assembly by ensuring the maintenance of finger 26 during all the operations of assembling the column of submunitions, without it being necessary to remove any means of temporary restraint.

 In addition, de-stacking of the submunitions can be carried out safely without initiating the self-destruction system, that is to say without releasing the finger 26.

 For this, a tubular tool 60 will be slidably mounted around the bodies 2. I1 will retain the end 27b of the finger 27 by its internal surface when the finger is found released by the adjacent submunition. The tongue 50 will then be reset manually in the groove 52 of the finger 27 in order to restore the arming security.

 It will be noted that, when the finger 27 bears against the internal surface of the tool, the end 27a always maintains the finger 26 axially. It will suffice to give the finger 27 a total length such that, when it is in the position shown in FIG. 3, the length L (length necessary for finger 27 to be able to release finger 26) is greater than length 1 (distance that end 27b must travel to come into contact with the internal surface of the tooling ) (see Figure 3).

Claims (10)

 1. Ammunition, in particular submunition intended to be ejected from a carrier projectile, for example a cargo shell, of the type comprising an explosive charge and a pyrotechnic chain for initiating the charge mounted in an armament security device , said chain including at least one switch element which is movable between a safety position and a position authorizing the operation of the pyrotechnic chain, and at least one locking member movable between a position for blocking the switch in the safety position and a switch release position, characterized in that it also comprises control means for releasing the switch when the munition is ejected, these control means comprising means for holding the locking member in its blocking position, these holding means being essentially constituted by a part of an adjacent munition on board the carg shell o.  2. Ammunition according to Claim 1, in which the pyrotechnic chain comprises a main striker (8) and a priming device (10) constituted by a detonator primer (11) carried by a movable slide (12) between a safety position and an arming position, characterized in that the slide (12) constitutes the aforementioned movable element forming a switch, and in that the locking member (25) constitutes at least one blocking security for the slide (12) in safety position until the munition is ejected.  3. Ammunition according to Claim 1, in which the pyrotechnic chain comprises a main striker (8) and a priming device (10) constituted by a detonator primer (11) carried by a mobile bucket grout (12) between a position of security and an arming position, and a self-destruction system (15) housed in the slide (12) and comprising an auxiliary striker (20) intended to authorize the operation of the self-destruction system (15) for causing the initiation of the detonator primer (11) with a determined delay after the release of the auxiliary striker (20), characterized in that the striker (20) constitutes the aforementioned movable element forming a switch, while the locking (25) constitutes at least blocking security of the striker (20) until the ejection of the ammunition (la).  4. Ammunition according to Claim 2 or 3, characterized in that the locking member (25) comprises at least one finger (26) movable in translation inside a first channel formed by an opening (29) provided in the body (6) of the arming security system (5) and a radial opening (30) provided in the slide (12), and a spring (31) which tends to eject the finger (26) to outside the first canal (29.30).  5. Ammunition according to Claim 4, characterized in that the locking member (25) comprises a second finger (27) movable in translation inside a second channel (33) formed in the body (6) of the arming safety device (5), this second channel (33) extending perpendicular to the first channel (29, 30) and opening out at least in part in this first channel so that the second finger (27) can immobilize the first finger (26), and in that a spring (37) tends to eject the second finger (27) outside the second channel (33).  6. Ammunition according to Claim 5, characterized in that the first finger (26) has an annular peripheral groove (35) in which the second finger (27) engages to immobilize the first finger (26) axially.  7. Ammunition according to Claim 5 or 6, of the type comprising a body (2) which contains the load (3), said body (2) being surmounted towards one end by the armament security device (5), said load (3), towards its end opposite to the armament security device (5), being hollow and coated with a coating (40) which delimits an internal space (41) intended to freely receive the armament security device ( 5) of said adjacent munition, characterized in that the finger (26, 27) is intended to come into abutment against the coating (40) of said adjacent munition which constitutes the aforementioned holding means.  8. Ammunition according to Claim 7, characterized in that, before stacking the ammunition (la, lb), a flexible blocking tab (50) projects into an opening (52) of the second channel (33) to axially immobilize the second finger (27), said tongue (50) extending radially outward in an oblique direction.  9. Ammunition according to Claim 8, characterized in that the body (2) of the adjacent ammunition (lb) extends beyond the load (3) by a cylindrical skirt (43) provided with an annular radial shoulder ( 44) on its internal wall, and in that during the stacking of the ammunition (la, lb), said shoulder (44) comes to bear on said tongue (50) to release it from the second channel (33).  10. Ammunition according to any one of Claims 3 to 9, characterized in that the other destruction system is of the thermal type for example and comprises a heat generator (16) intended to cause the initiation of the detonator primer ( 11) with a certain delay following the ejection of the ammunition and whatever the position of the slide (12)