FR2678724A1 - Preprogrammed safety and firming unit for a warhead - Google Patents

Abstract

This unit includes: a first train interruption safety unit consisting of the inert material of an interruption flap (16) opposing any transmission of a pyrotechnic priming effect towards the warhead (22) as long as the flap has not been able to be armed; a second safety system consisting of a shaft (24) abutted between the launcher system (26) and the flap (16), this shaft opposing the movement of the flap as long as the launcher system is present; a third safety unit consisting of a shaft (26) locking the flap (16) in safety position as long as the unit has not detected a sufficient level of acceleration to guarantee a minimum speed of the carrying projectile, and a fourth safety unit, called trajectory safety unit, designed in such a way as to hold the flap (16) in a safety position as long as the minimum safety distance has not been travelled.

Description

 The present invention relates to a safety and firing device for the initiation of pyrotechnic elements, in particular a charge carried for example by a self-propelled missile or projectile or not.

 The invention relates more particularly to a device of the type mentioned above designed in particular - on the one hand, so as to oppose the firing of the charge with pyrotechnic effects as long as the latter is not at a distance sufficient for the shooting staff to be able to ensure their safety, such a device is known by the general name "security and armament device", and it is designed so as to meet strict standards - on the other hand, in order to '' initiate the military charge, by electro-pyrotechnic means, beyond the safety distance mentioned above, according to an operating mode chosen by the shooter, before firing, from two possible modes. These two corresponding operating modes for example as will be seen below in instant operation or in delayed operation of a hollow charge of a projectile.

 The device according to the invention comprises a main body containing the mechanical, electrical and pyrotechnic elements, this main body closed by a closure plate containing in particular a primer and its electrical connection elements for igniting, an interruption flap comprising itself a pyrotechnic transmission relay and a means of controlling said shutter and it is characterized in that it further comprises - a first safety known as chain interruption safety constituted by the inert material of the shutter opposing any transmission of initiating pyrotechnic effect to the military charge as long as the flap could not arm - a second security known as tube security consisting of an arched shaft between the launching system of the projectile, for example a tube and the shutter, this shaft constituting a rigid stop opposing the movement of the shutter as long as the launcher system is present ; - a third safety device called acceleration level safety which consists of a shaft ensuring the blocking of the interruption flap in the safety position as long as the device has not detected a level of acceleration sufficient to guarantee a minimum speed at carrier projectile and - a fourth so-called trajectory safety device produced in the form of a timed delay system designed so as to maintain the flap in a safety position as long as the minimum safety distance has not been traveled.

 According to the invention, it is also possible to provide a fifth safety device designed so as to prohibit the electric firing of the primer until the flap has been completely released in the final position.

 According to an exemplary embodiment of the present invention, the third safety known as acceleration level safety comprises a pin holding the shaft which ensures the locking of the flap in the safety position, this pin being able to shear only when the force induced during the The acceleration of the carrier projectile is greater than a minimum force calculated beforehand to guarantee a normal departure of the carrier projectile.

 According to another exemplary embodiment of the present invention, the fourth safety device is designed in the form of a delay device driven by a lever rotating on an axis, this lever being itself driven at its end on the shutter side by a pin. , or similar fixed to the latter, and supported on another pin mounted in the blank of a toothed wheel engaged with a second wheel actuating an anchor / escapement mechanism.

 According to the present invention, means are also provided for generating and storing electrical energy ensuring the initiation of the military charge.

According to this invention, these means comprise on the one hand, a piezoelectric energy creation device implemented by one or more of the effects or forces of launch, propulsion or flight and, on the other hand, a device storage of this energy by capacitive means. According to a preferred embodiment of this invention, the energy creation device is produced in the form of a striker, constituted for example by the shaft of the third safety device or acceleration level safety device, this striker, during acceleration, violently striking one or more piezoelectric ceramics thus creating an electric field from charging the capacitor of the storage device.

 As mentioned above, the invention also provides for initiation of the military charge by electro-pyrotechnic means, beyond the safety distance, according to an operating mode which is chosen by the shooter from two modes possible operation, prior to firing.The device according to the invention, designed for this purpose is in the form of an external and independent control means of the carrying projectile comprising a handle or a control button provided with either a magnet with reversible polarity, either of two magnets mounted in opposite polarity and a receiver means integrated into the carrier comprising a movable magnet which, depending on its state (attracted or repelled) makes it possible to maintain or release a control control part. function under the effect of the forces or effects brought into play when the carrier leaves, the movement or the maintenance of said control part allowing the switching or the maintenance of a circuit pr also established, ensuring the desired operating mode, either immediate pyrotechnic operation or delayed pyrotechnic operation.

Other characteristics and advantages of the present invention will emerge from the description given below with reference to the appended drawings which illustrate exemplary embodiments thereof without any limiting character. On the drawings
Figures la to lc are schematic views in vertical section illustrating the operating principle of the security and arming device according to the present invention
Figures 2a and 2b are schematic plan views, representing the delay device constituting the fourth so-called trajectory safety of the device object of 1 invention, in the position before departure of the projectile and at the end of operation
Figure 3 is a schematic view showing the electrical assembly and the components of the device ensuring the generation and storage of energy for ignition
FIGS. 4a to 4d are schematic views similar to FIGS. fire;
Figure 5 is a schematic view showing an embodiment of the electrical connection of the device according to the invention;
Figure 6 is also a schematic view illustrating an example of primer and
FIGS. 7a and 7b are schematic views illustrating the two operating modes obtained thanks to the invention: instantaneous operation and delayed operation respectively.

 Reference is firstly made to FIGS. 1a to 1c, 2a, 2b and 3 which show, by way of example, the part of the safety and arming device of the device according to the present invention, this part being designed so as not to cause terminal or semi-terminal pyrotechnic operation on the trajectory only after the launch (or firing) of the projectile and only when the safety of the user personnel is guaranteed by the distance traveled by the projectile.

 The security and arming device comprises a main body designated as a whole by the reference 10 which contains the mechanical, electrical and pyrotechnic elements, this body being closed by a closure plate 12. The body contains in particular a detonator primer 14 and its electrical connection elements for igniting, an interruption flap 16 itself provided with a pyrotechnic transmission relay 18 and with a motor system produced here in the form of a spring 20. This flap 16 allows isolating the detonator primer 14 from its downstream pyrotechnic chain designated as a whole by the reference 22.

 The first security of the device, called chain interruption security, is therefore constituted by the inert material of the flap 16 which constitutes a physical barrier opposing any transmission of pyrotechnic effect from the primer 14 to the military pyrotechnic charge 22 until the shutter could arm.

 The second security, called tube security, consists of a shaft 24, mounted on one of the lateral faces of the flap 16, this shaft therefore being braced between the tube or the launcher system 26 and the interruption flap 16. It therefore constitutes a rigid stop which prevents the advancement (or arming) of the interruption flap 16 as long as the launcher system 26 is present.

 The third safety, called acceleration level safety, is produced here in the form of a shaft 28 mounted in a bore provided in the body 10 and which comprises a stud 32 at its end positioned in the body, this stud serving as a stop for locking to the shutter 16. This shaft 28 locks the shutter 16 in the safety position as long as the device has not detected a level of acceleration sufficient to guarantee a minimum speed for the carrier projectile. In the nonlimiting exemplary embodiment illustrated in the drawing, the shaft is held in the body 10 using a pin 30 which can only shear if the force induced during acceleration is greater than one minimum force calculated to guarantee a minimum sufficient speed of the carrier. Thus, the erasure of the blocking due to the shaft 28, when the pin 30 shears, is obtained under the effect of maintaining the acceleration for an additional time.

 It is understood that when the two events exiting the launch tube or the launcher system 26 and minimum level of acceleration have been detected, the two safety elements constituted by the shafts 24 and 28 retract thus releasing the shutter 16 which, under the effect of its mainspring 20 can then advance to ensure alignment of the pyrotechnic chain 14, 18, 22. FIG. 1a represents the safety and arming device in the locked position, FIG. 1b represents this same device during the safety distance and FIG. 1c illustrates the device after the safety distance, the elements 14, 18, 22 of the pyrotechnic chain then being aligned.

 We have seen above that the invention also provides a fourth so-called trajectory safety device making it possible to delay arming for a time corresponding to the flight time of the projectile over the safety distance. This fourth safety device is produced in the form of a timer-type retarder system, that is to say, an anchor system rocking on the toothing of an escapement wheel and keeping the flap 16 in the safety position both the minimum safety distance has not been traveled (for the minimum effect mentioned above).

 In this exemplary embodiment, illustrated by FIGS. 2a and 2b, this trajectory safety comprises a lever 34 rotating on its axis 36 and which is driven at its end on the flap side 16 by a pin 38 fixed to the latter.

The lever 34, at its other end, is supported on a pin 40 which is integrated in the input wheel 42 of the clock system, engaged on the escape wheel 44 on which the anchor system 46 can tilt The lever 34, driven by the mainspring 20 of the shutter via this shutter 16 and the pin 38, bears on the pin 40 (FIG. 2a) until the rotation of the input wheel 42 , causing the rotation of the escape wheel 44, itself braked by the rapid tilting of the anchor 46, sufficient to allow the lever to escape (FIG. 2b) therefore the release of the flap 16 which can then fully arm under the pursuit of the motor effect of the spring 20 thus ensuring the alignment of the elements of the pyrotechnic chain (position illustrated in FIG. 1c, as described above).

 According to the present invention, it is also possible to provide a fifth safety device designed so as to maintain the shunted primer terminals by electrically connecting them to conductive strips 48 bearing on a short-circuit track 50 (see FIG. 3) secured to the flap. 16 until final release of the latter (at least at the safety distance defined above).

 When the shutter is fully armed (FIG. 1c) the pyrotechnic relay 18 which it contains is physically aligned with the rest of the pyrotechnic chain and it is therefore able to transmit the ignition to the military charge 22.

 The invention also provides autonomous means for creating and storing energy for igniting pyrotechnic components, electrically, on receipt of a short-circuit signal. An exemplary embodiment of these means is illustrated in FIG. 3. It consists in using the inertial forces linked to the acceleration undergone by the components internal to the projectile to violently launch a striker on a piezoelectric ceramic system. This device therefore comprises one or more piezoelectric ceramics 52 positioned so that they can be violently struck by the end of the shaft 28 during acceleration from the projectile. The piezoelectric ceramic (s) 52 are positioned in an integrated body 54 to the projectile and assembled on the body 10 previously described, and they are enclosed with their armatures forming capacitance electrodes 56 between a hammer 58 and an anvil 60 of metal which make it possible to distribute the punctual impact forces of the striker 28 in a uniform mechanical load .

 A device is also provided for storing the energy thus created by piezoelectric means. This device provides storage by capacitive channel filtered by a diode which maintains the charge generated when the forces or effects generated during the impact of the shaft 28 on the piezoelectric ceramic device have ceased or modified their action. In the embodiment illustrated in FIG. 3, the piezoelectric effects of the ceramic (s) 52, compressed during the impact of the striker 28, are collected by the two conductive plates 56, the latter being connected according to the polarization suitable for a circuit comprising a diode 62 and a capacitor 64, soldered on an electrical circuit board 66 which also includes the initiating short-circuit strips 48 of the safety and arming device described above. mechanical stress of the ceramic 52, the electric field it generates is balanced in the form of electric charges between the capacity of its armatures 56 and that of the capacitor 64 through the diode 62 suitably polarized. The capacitor is then charged with an electrical energy which can no longer flow except in its circuit of use Cu, placed downstream from its terminals.

 According to the invention, the percussion or compression force obtained using the striker shaft 28 can be subjected to one or more piezoelectric elements such as 52, mechanically mounted in series and connected in parallel according to their electrical polarization, in order to increase the energy generated. It is obviously possible to envisage other variants without departing from the scope of the present invention, for example by using a pressure or a propulsion force, a change in temperature or one or more effects due to the trajectory, or even several effects combined to obtain the piezoelectric operation sought.

 The device according to the invention also provides, as has already been mentioned above, means making it possible to initiate the military charge by electropyrotechnic means beyond the safety distance, according to an operating mode chosen by the shooter among two possible operating modes, prior to shooting. According to the invention, the triggering of this initiation is obtained by an external device which will be described below with reference to FIGS. 5 and 7a and 7b, (target detector or delay device for example) which generates at this instant a signal from the "electrical short-circuit" type. The two possible operating modes can correspond, according to a preferred example of implementation of the present invention, either to instantaneous operation, or to delayed operation of a hollow charge of projectile on reception. of the target detection signal. It is thus possible for the shooter to choose between a "perforating" effect in the event of shooting on "hard" armor and a "blast and projections" effect in the event of shooting on "light" armor such as, shelters, vehicles covered by example. In the first case, the perforating effect is ensured by the positive distance between the shielding and the hollow charge and in the second case, the charge can operate after passing through the light shielding, for example the walls of a shelter, therefore with an optimized destructive effect on its human and material content.

 This programming and control device according to the present invention will now be described with reference to FIGS. 4a to 4d in which the constituent elements of the security and arming device described above are recognized with reference to FIGS. 1a to 1c.

 As can be seen in these FIGS. 4a to 4d, this device comprises a handle or external control button generally designated by the reference 68 in which two magnets 70a and 70b are provided mounted in opposite polarity. By manual rotation, the operator can therefore bring this handle 68, by rotation about its axis 72, to one of its two stops identified for example by pictograms representing in one case an armored vehicle (hard armor) and in the other case a shelter or a house (light shielding) and designated in the drawings by the reference 71. Each of these positions corresponds to the alignment of one of the magnets 70a, 70b, with a third magnet 74 which is integrated in the safety rod or shaft 24 of the safety and arming device described above, this third magnet 74 being positioned, in a movable manner in a bore provided in the rod 24, so that it can move under the effect of magnetic attraction or repulsion forces. The device also comprises a conductive control part, produced in the form of a metal rod 76 which bears on the magnet 74 thanks to the presence of a slot 78 made in the shaft or security rod 24, this slot 78 passing through the rod 24 in a radial passage as seen in Figures 4a to 4d.

 At rest, the components of this programming system occupy the position represented by FIG. 4a and, in this position, the operator chooses the desired operating mode by operating the handle 68.

 When the projectile leaves, the inertial forces applied to the metal control part 76 tend to eject it from its support, the latter being produced in the form of an electrical outlet of the "Jack" type designated here as a whole. by the reference 80 and which is fixed on the body 54. The receiver magnet 74 then makes it possible, according to its pre-selected position during the prior operation of the handle 68, to maintain (FIG. 4c) or to authorize (FIG. 4d) the ejection of the control part 76. According to one or other of these operating cases, respectively, the electrical circuit of the "Jack" socket therefore remains blocked in position A (by means of the electrical control, Figures 4a and 4c) or switches to circuit B (Figures 4b and 4d). The terminal operating circuit is therefore established from this instant. In the case of the embodiment described here, it makes it possible to initiate the impact of the projectile on its objective one or the other of two half detonator primers 82a and 82b mounted head to tail as can be seen in FIGS. 5 and 6. The primer therefore includes a side 82a with immediate pyrotechnic operation and, another side with pyrotechnic operation delayed by the presence of a composition delay 84 interposed between the sensitive composition of the primer 82b and the power composition 86.

Thus, the short circuit caused in a conventional manner in the warhead 88 of the projectile during the impact of the latter on the target 90 is thus passed on to one or the other of the sides of this primer. The device according to the invention therefore makes it possible to trigger the firing of a military charge of a projectile, for example with a hollow charge, before the intended target (case of an attack by an armored vehicle) or after a delay of delay allowing it to penetrate target 90 beforehand (in the case of an attack on a light fortification for example).

 The two operating modes described above are illustrated by FIGS. 7a and 7b in which we find the main components of the device according to the invention as described above and the operating wiring used during the short circuit d 'warhead 88.

 It remains to be understood that the present invention is not limited to the various embodiments described and or represented here, but that it encompasses all variants thereof.

Claims (12)

1. Safety and firing device preprogrammed for the initiation of pyrotechnic elements, in particular a military charge carried by a self-propelled or non-propelled machine or projectile which comprises a main body (10) containing the mechanical elements, electrical and pyrotechnic, this main body, closed by a closure plate (12) containing in particular a primer (14) and its electrical connection elements for igniting, an interruption flap (16) itself comprising a relay pyrotechnic transmission (18) and a means (20) ensuring the movement of said flap and it is characterized in that it further comprises - a first safety known as chain interruption safety constituted by the inert material of the flap (16) opposing any transmission of initiating pyrotechnic effect to the military charge (22) as long as the nota shutter was able to arm; - A second security called tube security consisting of a shaft (24) braced between the launcher system (26) of the projectile, in particular a launching tube and the interruption flap (16), this shaft constituting a rigid stop opposing the movement of the interruption flap as long as the launcher system is present - a third security known as acceleration level security which consists of a shaft (28) ensuring the blocking of the interruption flap in the safety position as long as that the device has not detected a sufficient acceleration level to guarantee a minimum speed for the carrier projectile and - a fourth so-called trajectory security produced in the form of a timed delay system (34; 42; 44; 46) designed to maintain the flap (16) in a safety position until the minimum safety distance has been traveled. 2. Device according to claim 1 characterized in that it further comprises, a fifth security designed so as to prohibit the electric firing of the primer as long as the flap (16) has not been completely released in position final. 3. Device according to one of claims 1 or 2 characterized in that the third safety known as acceleration level safety comprises a pin (30) holding the shaft (28) which ensures the locking of the flap (16) in position safety, this pin can only shear when the force induced during the acceleration of the carrier projectile is greater than a force calculated beforehand to guarantee a departure of the carrier projectile at a minimum speed. 4. Device according to any one of the preceding claims, characterized in that the fourth safety device is designed in the form of a time-delay device driven by a lever (34) rotating on an axis, this lever being itself driven to its end on the shutter side (16) by a pin (38) or the like fixed to the latter, and pressed on another pin (40) mounted in the blank of a toothed wheel (42) engaged with a wheel d exhaust (44) actuated by an anchor mechanism (46). 5. Device according to any one of the preceding claims, characterized in that said fifth safety device is designed so as to keep the primer terminals shunted by conductive strips (48) in abutment on a short-circuit track (50) integral of the flap (16) until final release of the latter. 6. Device according to any one of the preceding claims, characterized in that it comprises autonomous means (28, 52, 64) making it possible to generate and store the electrical energy ensuring the initiation of the military charge. 7. Device according to claim 6 characterized in that these means comprise on the one hand, a piezoelectric energy creation device implemented by one or more of the effects or forces of launch, propulsion or flight and , on the other hand, a device for storing this energy by capacitive means. 8. Device according to claim 7 characterized in that the energy creation device is produced in the form of a striker, which may be constituted by the shaft (28) of the third safety device or safety device for acceleration level, this striker, during acceleration violently striking one or more piezoelectric ceramics (52) thus creating an electric field from charging the capacitor (64) of the energy storage device. 9. Device according to any one of the preceding claims, characterized in that it further comprises means making it possible to initiate the military charge by electropyrotechnic means, beyond the safety distance, according to an operating mode. which is chosen by the shooter from two possible operating modes, prior to shooting. 10. Device according to claim 9 characterized in that said means are in the form of an external and independent control means of the carrying projectile comprising a handle or a control button (68) provided with either a magnet with reversible polarity , or two magnets (70a, 70b) mounted in polarity opposition and a receiving means, constituted by a third magnet (74) integrated in the safety rod (24), this third magnet being positioned in a movable manner in said rod so as to be able to move under the effect of the forces of attraction or magnetic repulsion, so as to, depending on its state, attracted or repelled, ensure the maintenance or the release of a function control part, consisting of a metal rod (76) resting on said third magnet (74), under the effect of the forces or effects brought into play when the carrier projectile leaves, the movement or the maintenance of said control part allows nt switching or maintaining a previously established circuit, ensuring the desired operating mode, either immediate pyrotechnic operation or delayed pyrotechnic operation. 11. Device according to claim 10 characterized in that the support of the control part (76) is produced in the form of an electrical outlet of the "Jack" type (80) fixed on the body (54) of the device, the electrical circuit of this socket (80) remaining blocked in one of its positions (A) or tilting on the other position (B) according to one or other of the operating cases pre-established by the operation of said handle ( 68). 12. Device according to any one of the preceding claims, characterized in that it comprises a detonator primer comprising two half-primers (82a, 82b) mounted head to tail, one of the half-primers enabling pyrotechnic operation to be ensured immediate and the other half-primer making it possible to obtain a delayed pyrotechnic operation due to the presence of a delay composition (84) which is interposed between the sensitive composition of the half-primer and the power composition (86).