FR2660749A1 - System for sequential, controlled and automatic triggering of a plurality of pyrotechnic payloads - Google Patents

Abstract

The present invention relates to a system for sequential, controlled and automatic triggering of a plurality of pyrotechnic payloads (100, 102, 104) characterised in that it comprises: electrical control means (200) including only two output terminals (206, 208), and automated distributor means (300, 302, 304) interposed between the electrical control means (200) and the various pyrotechnic payloads (100, 102, 104) so as to apply to each of them, successively and according to a predetermined timing, the control signal originating from the control means.

Description

 The present invention relates to the field of pyrotechnic systems.

 The present invention relates more precisely to a system of sequential, controlled and automatic triggering of a plurality of pyrotechnic payloads.

 Different sequential triggering systems for pyrotechnic charges have already been proposed.

 However, the systems hitherto proposed are not entirely satisfactory.

 Many of these systems include in particular very long lengths of wire intended to connect electrical control means and each of the pyrotechnic charges. These systems are quite expensive and their implementation is quite complex.

 Other systems include pyrotechnic delays between the various charges. These systems are also quite expensive. Furthermore, these systems do not allow precise control of the time difference between the ignition of the different charges.

 The object of the present invention is to propose a new system for sequentially triggering a plurality of pyrotechnic payloads which avoids the drawbacks of the prior art.

 The object of the present invention is therefore to propose a new system which uses neither long lengths of connecting wires nor a large number of pyrotechnic delays.

 This object is achieved according to the present invention thanks to a system comprising - electrical control means comprising only two output terminals, and - automated distributor means interposed between the electrical control means and the various pyrotechnic payloads for successively applying to each of these, and according to a predetermined timing, the control signal from the control means.

 According to a preferred characteristic of the present invention, the distributing means comprise a plurality of switches positioned respectively close to the various payloads so as to be requested to close respectively during the successive implementation of the various loads.

 Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings given by way of nonlimiting examples and in which - FIG. 1 represents a general diagram of a first embodiment of a trigger system according to the present invention, - Figure 2 shows the general diagram of a first variant of a trigger system according to the present invention, - Figure 3 shows the general diagram of a second variant of a trigger system according to the present invention, - FIG. 4 represents a schematic view in axial section of a system according to the present invention produced in the form of a cartridge, - FIGS. 5, 6, 7 and 8 show similar schematic views in axial section of alternative embodiments of the system, - Figure 9 shows a schematic view in c oupe of an igniter according to the present invention, at rest state, - Figure 10 shows a schematic sectional view of the same igniter, after implementation thereof, - Figure 11 shows schematically another embodiment of the system according to the present invention in the form of a bar, - Figure 12 schematically shows another embodiment of the system according to the present invention in the form of several rows of payloads juxtaposed horizontally, - Figure 13 shows schematically another mode embodiment of the system according to the present invention in the form of a complete charger, and - Figure 14 shows a variant of the system diagram.

 As indicated above, the triggering system in accordance with the present invention essentially comprises - a plurality of pyrotechnic payloads 100, 102, 104, - electrical control means (200) with two output wires 206, 208 and - means of automated distributors interface 300, 302, 304 interposed between the electrical control means 200 and the various pyrotechnic payloads 100, 102, 104 to apply successively to each of these, and according to a predetermined timing, the control signal from the means 200.

 In Figure 1 the payloads have the general references 100, 102, 104. These loads can be of very diverse natures as will be explained below. Three charges 100, 102, 104 are shown in FIG. 1. Of course, the number of charges is not limiting.

 In FIG. 1, the electrical control means 200 comprise a continuous electrical supply 202 and a main control interrupter 204. The supply 202 and the main switch 204 are connected in series between the two output wires 206, 208 which will be referred to as respectively thereafter ground wire and active wire.

 Those skilled in the art will readily understand that the momentary closing of the main switch 204 makes it possible to apply a voltage pulse between the output wires 206, 208.

 The distribution means shown in FIG. 1 comprise different switches 300, 302, 304 placed in series on the active wire 208. More specifically, there are provided N-l switches 300, 302, for N loads 100, 102, 104.

 Each payload 100, 102, 104 comprises an igniter, or equivalent means 101, 103, 105 connected between the ground wire 206 and the active wire 208. More precisely still the igniters 101, 103, 105 of the various charges 100, 102 , 104 are placed between different intermediate points of the active wire 208 and the ground wire 206. For this the active wire 208 is split into a plurality of sections 2081, 2082, 2083, separated by the switches 300, 302, 304, mentioned above.

 Thus, the first igniter 101 is directly connected in parallel with the output wires 206 and 208 of the control means 200. The first switch 300 is interposed between the first section 2081 of the active wire 208 and the second section 2082 thereof. The second igniter 103 is connected between this second section 2082 and the ground wire 206. The second switch 302 is interposed between the second section 2082 of the active wire 208 and the third section 2083 thereof. The third igniter 105 is connected between this third section 2083 and the ground wire 206, etc ...; that is to say that in the case of a system comprising more than three loads the basic structure shown in FIG. 1 is generalized.

 At rest the switches 300, 302, 304 are open.

 The switches 300, 302, 304 are designed to be actuated on closing during the successive implementation of the various loads. The first switch 300 is requested to close after implementation of the first load 100. The second switch 302 is requested to close after implementation of the second load 102, etc.

 Various embodiments of the switches 300, 302, 304 will be described below.

 Essentially, the operation of the system shown in Figure 1 is as follows. Originally the switches 300, 302, 304 being open, only the igniter 101 is connected in parallel with the output wires 206, 208. Thus, during the application of a voltage pulse between the wires 206, 208, occasioned by the temporary closing of the switch 204, the igniter 101 is initiated and ensures the implementation of the load 100. This implementation induces, for example by thermal or mechanical effect as will be described later, the closing of the first switch 300. The second igniter 103 is then connected in parallel with the output wires 206, 208. The second igniter can therefore be initiated during the application of a second voltage pulse between the wires 206, 208, caused by a new temporary closing of the switch 204. The initiation of the second igniter 103 ensures the implementation of the second charge 102, which in turn commands the closing of the second switch 302, etc.

 FIG. 2 shows an alternative embodiment of the basic diagram of the system according to the present invention, in which the switches 300, 302, 304 are replaced by reversing switches 3000, 3002, 3004. At rest, the reversing switches 3000, 3002, 3004 connect an upstream section of the active wire 208 to an associated igniter 101, 103, 105. When the reversing switches 3000, 3002, 3004 are activated, following the implementation of the associated load, they remove the connection mentioned above between the upstream section of the active wire 208 and the associated igniter and on the other hand provide an electrical connection between the upstream section of the active wire and the downstream section.

 Thus at rest, the first reversing switch 3000 connects the first section 2081 of the active wire 208 to the igniter 101. On the other hand, after solicitation following the use of the load 100, the first reversing switch 3000 connects the first section 2081 of wire active at the second section 2082 of it, etc.

FIG. 3 shows another alternative embodiment of the system according to the present invention comprising several assemblies similar to those described above with reference to FIGS. 1 and 2, connected in parallel between the two output wires 206, 208 of the means of 200 command. More specifically, FIG. 3 shows a system comprising three sets referenced respectively.
I, J, K, identical to the assembly represented in FIG. 1 and connected in parallel with the output wires 206, 208. I1 follows that when a first voltage pulse is applied between the output wires 206 , 208 following the temporary closing of the switch 204, the first igniter 101.1, 101.5, 101.K, of each of the sets I, J, K, is initiated and ensures the implementation of the associated load 100.I, 100.J, 100.K. The implementation of these loads induces the closing of the switches 300.I, 300.J, 300.K, to then authorize the initiation of the second igniters 103.1, 103.J, 103.K during the application of the second voltage pulse, etc ...

 Of course the system according to the present invention is likely to include a number of sets I, J, K, in parallel, different from three.

 FIG. 4 shows a particular embodiment of the system according to the present invention in which several charges 100, 102, 104 are superposed axially in a cartridge 10. In the present case, the system comprises three charges 100, 102, 104.

This number is not limitative.

 More precisely, the cartridge 10 comprises a socket 12 centered on an axis 14. The socket 12 is provided with a base 16 at its base and closed at the front by a sealed ejectable cover 18. The charges 100, 102, 104 are superimposed axially inside the socket 12. The base carries an electrically conductive stud 20 schematically shown in FIG. 4. The socket 12 is also made of electrically conductive material. Electrically insulating means are inserted between the base 16 of the socket and the stud 20 so that the latter can be connected respectively to the ground wire 206 and to the active wire 208.

 Each of the charges 100, 102, 104 is housed in an ejectable casing 110, 120, 130. The ejectable casings 110, 120, 130 comprise a base 111, 121, 131 which houses an ejection charge, an igniter 101, 103, 105 and safety means represented schematically under the reference 112, 122 and 132 in FIG. 4. The igniters 101, 103, 105 are connected between the output wires 206, 208 via the distributing means 300, 302, 304 as indicated previously. Thus, the successive application of voltage pulses between the output wires 206, 208 allows the successive initiation of the igniters 101, 103, 105 and therefore the ejection and the successive implementation of the charges 100, 102, 104.

 The cover 108 is ejected during the ejection of the first load 100. In a manner known per se, the safety means 112, 122, 132 can for example comprise misalignment drawers or any equivalent means well known to those skilled in the art. 'art.

 The switches 300, 302, 304 and / or reversing switches 3000, 3002, 3004 can be the subject of numerous embodiments.

They can be of the pyrothermic, electromechanical, pyroelectromechanical or electronic type, for example.

 FIG. 5 shows an embodiment of switch 300, 302 of the electromechanical type.

 FIG. 5 shows a cartridge type system comprising three assemblies 110, 120, 130, each containing a charge 100, 102, 104 superposed axially in a socket 12 having a base 16 housing a stud 20 and provided with a cover 18 FIG. 5 shows the three igniters 101, 103, 105, placed in the base of the assemblies 110, 120, 130. These igniters are connected to the socket 12 and to the pad 20 by means of the electromechanical switches 300, 302. forming the aforementioned distributing means.

 As previously indicated, the switches 300, 302 open at rest are designed to be requested to close when implementing an upstream load. For this, the switches 300, 302 can be positioned as shown diagrammatically in FIG. 5 on the front end of the ejectable assemblies 120, 130.

 The first igniter 101 is connected between the socket 12, which is itself connected for use to the ground wire 206 and the stud 20, which is itself connected to the use for the active wire 208.

 The second igniter 103 is connected on the one hand to the socket 12, on the other hand via the switch 300 to the active wire 208. This switch 300 is placed on the front of the second ejectable assembly 120. At rest , The switch 300 is open. I1 is held in this open position by the upstream ejectable assembly 110 which serves as a stop. The switch 300 is however requested upon closing. I1 can thus pass into the closed position during the ejection of the first assembly 110 to authorize the initiation of the second igniter 103.

 The third igniter 105 is connected on the one hand to the socket 12, on the other hand via the switch 302 to the active wire 208. This switch 302 is placed on the front of the third ejectable assembly 130. At rest , switch 302 is open. It is held in this open position by the upstream ejectable assembly 120 which serves as a stop. The switch 302 is however requested to close. I1 can thus pass into the closed position during the ejection of the second set 120 to authorize the initiation of the third igniter 105.

 In FIG. 5, the payloads are represented diagrammatically under the references 100, 102, 104, and the associated ejection charges under the references 113, 123, 133.

 FIG. 6 shows another alternative embodiment of a system in accordance with the present invention arranged in the form of a cartridge comprising several charges superposed axially which differs from the aforementioned embodiment represented in FIG. 5 simply by the fact that the electromechanical switches 300, 302 shown in FIG. 5 are replaced by pyrothermal type switches.

 The term "pyrothermal type switch" means a switch open at rest but requested to close upon application of a temperature exceeding a given threshold. Such a pyrothermal type switch can for example be produced in the form of two wires insulated at rest but capable of being connected during the melting of a conductive body 301, 303 comprising a fusible composition as shown diagrammatically in FIG. 6. For this of course the insulated wires and the associated conductive fuse body 301, 303 must be placed on the front of the respective assemblies 120, 130 to be sensitive to the generation of heat generated by the upstream assembly 110, 120 respectively during its ejection.

 FIG. 7 shows another alternative embodiment of a system in accordance with the present invention arranged in the form of a cartridge comprising several charges superposed axially which differs from the aforementioned embodiment represented in FIG. 5 simply by the fact that the switches 300, 302 shown in FIG. 5 are incorporated in the igniters 101, 103. This is thus in the form of an igniter with three output wires.

 An embodiment of such a three-wire igniter will be described below with reference to FIGS. 9 and 10.

 There is shown in Figure 8 another alternative embodiment of a system according to the present invention arranged in the form of a cartridge comprising several charges superposed axially which differs from the above embodiment shown in Figure 5 by the fact that the switches 300, 302 shown in Figure 5 are grouped in a housing 40 adjacent to the base 16 of the cartridge. Thus, the igniters 101, 103, 105 are each connected on the one hand to the socket 12, on the other hand to an outlet respectively associated with distribution means placed in the housing 40. These distribution means can take the form of a module electronics designed to successively apply a voltage pulse to these various outputs, with a controlled time difference between these various pulses. The distributing means can also take the form of an equivalent electromechanical module.

 Note however that the particular embodiment shown in FIG. 8 is currently considered by the applicant to be less efficient than the embodiment previously described insofar as this particular embodiment requires a direct connection between each of the igniters 101, 103 , 105 and the distributor 40.

 Preferably the distributor 40 is recoverable.

 We will now describe the three-wire igniter shown in FIGS. 9 and 10.

 This igniter 50 comprises an electrically insulating support 52 which carries three wires referenced 54, 56, 58. The support 52 can be produced for example in the form of a printed circuit. The wires 54, 56 are connected at one of their ends by a filament 60 coated in an ignition composition 62. The other end of the wires 54, 56 is intended to be connected respectively to the ground wire 206 and to the wire active 208. Preferably the wire 56 is provided with a fuse 64.

 The third wire 58 is placed near the wire 56. At rest, however, it is electrically isolated from the latter. A pyrothermic composition, such as a pyrotechnic composition or an aluminothermic composition 66, is placed close to the wires 56 and 58 or coats them. The composition 66 is also placed close to the composition 62 so that the composition 66 is heated and can melt during the initiation of the ignition composition 62 so as to then connect the wires 56 and 58.

 The three-wire igniter shown in FIG. 9 and comprising a fuse 64 can be likened to a reversing switch. Indeed, at rest the wires 54, 56 are connected by the filament 60, while the wires 56 and 58 are electrically isolated.

 After applying a voltage pulse between the wires 54, 56, the ignition composition 62 is initiated, which leads to the opening of the fuse 64 and the initiation of the composition 66 to connect the wires 56, 58 .

 Thus after initiation, the igniter is found in the configuration shown in Figure 10 where the wires 54, 56 are electrically isolated while the wires 56, 58 are interconnected.

 Such an igniter incorporating reversing switch means can be used for producing the system shown in FIG. 2.

 The igniter shown in FIGS. 9 and 10 could be produced without a fuse 64. In this case, I1 could be assimilated to a simple switch capable of being used for producing the system shown in FIG. 1.

 The means 66 designed to connect the wires 56, 58 after initiation of the composition 62 can be the subject of various variant embodiments. Recall that according to the embodiment shown in Figure 9 these means 66 comprise a pyrothermic composition.

 As a variant, these means 66 can be produced in the form of a semiconductor junction using the effect known to those skilled in the art under the expression "uncontrolled avalanche effect". It is a semiconductor junction positioned relative to the supply polarization to be blocked at rest, but capable of switching to the on state during a determined heating. More precisely, such an effect is generally reversible as long as the temperature applied to the junction remains within a given range, and becomes irreversible beyond a threshold temperature.

 Thus, the use of such a semiconductor junction between the wires 56, 58 makes it possible to have at rest an open switch between these wires 56, 58 and a closed switch, reversibly or not after initiation of the composition d ignition 62 causing the thermal effect necessary for the change of state of the semiconductor junction.

 We have previously described systems grouping a plurality of payloads in the form of a cartridge. The invention is not limited to this arrangement. FIG. 11 thus represents a system grouping together a plurality of payloads 100, 102, 104, etc. in the form of a row juxtaposed horizontally on a support bar 70.

 Another variant is shown in FIG. 12 in which the system groups together payloads in the form of several rows juxtaposed horizontally on a common support 72.

 Finally, FIG. 13 shows another variant in which the system is arranged in the form of a complete charger housing several rows of charges in a housing 74 and provided with two electrically conductive pads intended to be connected to the output wires 206, 208 of external control means.

 The variants of arrangement in the form of a bar or a charger can be used for example for the design of the system shown in FIG. 3.

 The controlled time difference between the initiation of two successive charges can be defined by means controlling the timing of the closing and opening of the switch 204. In this case, the charges are initiated successively during the application of the voltage pulses between the output wires 206, 208.

 To avoid the untimely initiation of several charges during the generation of a single pulse, means for shaping the pulses can be interposed between the control means 200 and the distributing means 300. These shaping means can be formed for example of monostables and / or capacitor modules.

 One can also provide for the permanent closure of the switch 204 to define a continuous supply between the output wires 206, 208. In this case the time difference between the initiation of two successive charges is defined simply by the response time to the closing of switches 300, 302, 304 and / or reversing switches 3000, 3002, 3004.

 As appears from the preceding description, the main advantage of the present invention lies in the design of control means 200 comprising only two output wires.

 The expression "payload" used in the context of the present invention should not be limiting, it encompasses all types of pyrotechnic charges known to those skilled in the art, whatever their particular arrangement, in the form of main charge, of underload or their packaging as indicated above (cartridge, bar, complete charger ...).

 In addition, the electrical diagram of the system can be the subject of numerous variants. We thus see in Figure 14 an alternative embodiment of Figure 1 wherein the switches 300, 302, 304 are not placed in series between different sections of the active wire, but the active wire 208 is continuous and the switches 300, 302 , 304 are placed in derivation of this active wire 208, to respectively connect the various igniters 103, 105 between the ground wire 206 and the active wire 208, the igniter 101 remaining directly connected to the output of means 200.

 In the case where the distributor means are of the inverter type, for example in the case of a three-wire igniter when the latter is equipped with a fuse, it is possible to provide test means for checking the state of the links. The tilting of the inverter and / or the opening of the fuse makes it possible to verify the initiation of the load.

 It will be noted that the system according to the invention makes it possible to use the state of the prior art of electrical control systems, insofar as it does not modify the previous energy requirements.

 We previously mentioned in the description a variant of switches 300, 302, 304, or reversing switches 3000, 3002, 3004 of pyroelectromechanical type. This means all types of switches or reversers whose mechanical switching is controlled by heat. I1 can be two wires initially kept separated by an electrically insulating sheath capable of melting during the implementation of an associated load to allow the contacting of your wires.

 It will be noted that, according to the embodiments represented in FIGS. 5, 6 and 8, the igniters 101, 103, 105 as well as the associated unloading charges 113, 123, 133 are placed on the assemblies 110, 120, 130 that they are intended to initiate and deposit respectively. In this case, the switches 300, 302, 301, 303 are on the other hand placed on the downstream assemblies or in the known housing 40.

 On the other hand, in the case of embodiment of FIG. 7, the igniters 101, 103 housing the switches intended to allow the initiation of downstream charges, the igniters 101, 103 as well as the associated unloading charges 113, 123 are placed on the '' immediately downstream of the one they are intended to initiate and deposit respectively.

Claims (26)

 1. A controlled and automatic sequential triggering system for a plurality of pyrotechnic payloads (100, 102, 104) characterized in that it comprises - electrical control means (200) comprising only two output terminals (206, 208), and - automated distributor means (300, 302, 304) interposed between the electrical control means (200) and the various pyrotechnic payloads (100, 102, 104) for successively applying to each of them, and according to a predetermined timing, the control signal from the control means.  2. System according to claim 1, characterized in that the distributing means comprise a plurality of switches (300, 302, 304) positioned respectively close to the various payloads (100, 102, 104) in order to be stressed at closing respectively during the successive implementation of the various loads.  3. System according to claim 2, characterized in that the switches (300, 302, 304) are of electromechanical type.  4. System according to claim 2, characterized in that the switches (300, 302, 304) are of the pyrothermal type.  5. System according to claim 2, characterized in that the switches (300, 302, 304) are of pyroelectromechanical type.  6. System according to claim 5, characterized in that the switches (300, 302, 304) of pyroelectromechanical type perform a mechanical switching controlled by heat.  7. System according to one of claims 5 or 6, characterized in that the switches (300, 302, 304) of the pyroelectromechanical type comprise two wires maintained initially separated by an electrically insulating sheath capable of melting during implementation an associated charge to authorize the contacting of these wires.  8. System according to claim 4, characterized in that the switches (300, 302, 304) each comprise two electrically isolated wires at rest and a fusible composition (301, 303) able to connect the electric wires after implementation of 'an adjacent payload.  9. System according to one of claims 1 to 8, characterized in that the distributing means comprise electrical switches incorporated respectively in igniters (101, 103) associated with the payloads (100, 102).  10. System according to claim 9, characterized in that the igniters (101, 103) have three output wires.  11. System according to claim 1, characterized in that the distributing means comprise switches grouped in a common housing, each of the charges comprising an igniter connected directly between a ground wire of the housing and an associated active output thereof.  12. System according to claim 11, characterized in that the switches are of electronic type.  13. System according to claim 11, characterized in that the switches are of electromechanical type.  14. System according to one of claims 1 to 13, characterized in that the distributing means comprise reversing switches (3000, 3002, 3004).  15. System according to one of claims 1 to 14, characterized in that it comprises several assemblies (1, J, K) each comprising several payloads arranged to be implemented successively, connected in parallel between the wires of output (206, 208) of the control means (200).  16. System according to one of claims 1 to 15, characterized in that the control means (200) comprise a continuous electrical supply (202) connected in series with a switch (204).  17. System according to one of claims 1 to 16, characterized in that the various payloads (100, 102, 104) are grouped in a common socket (12) like a cartridge.  18. System according to one of claims 1 to 16, characterized in that the various payloads (100, 102, 104) are juxtaposed on a common support (70, 72).  19. System according to one of claims 1 to 16, characterized in that the various payloads (100, 102, 104) are grouped in a common housing (74) provided with two electrical output pads forming a complete charger.  20. System according to one of claims I to 19, characterized in that it comprises a plurality of igniters (101, 103, 105) arranged on the load boxes (100, 102, 104) that they are intended to initiate respectively.  21. System according to one of claims 1 to 19, characterized in that a plurality of igniters (101, 103) disposed on the load boxes (100, 102, 104) located immediately downstream of the loads that they are intended to initiate respectively.  22. An igniter for implementing pyrotechnic charges, characterized in that it comprises - an electrically insulating support (52) which carries - three electrically conductive wires (54, 56, 58), - a filament (60) connecting a first (54) and a second wire (56), - an ignition composition (62) coating the filament and - sensitive means (66) capable of ensuring an electrical connection between the second (56) and the third wire (58 ) after initiation of the ignition composition (62).  23. An igniter according to claim 22, characterized in that the means (66) are heat-sensitive.  24. An igniter according to claim 23, characterized in that the sensitive means (66) comprise an aluminothermic composition.  25. An igniter according to claim 23, characterized in that the sensitive means (66) comprise a semiconductor junction exploiting the uncontrolled avalanche effect.  26. An igniter according to one of claims 22 to 25, characterized in that a fusible element (64) is provided on the second wire (56).