EP0075496A1 - Safety and arming arrangements for underwater fuzes - Google Patents

Abstract

1. Safety and arming device for priming of undersea charges, notably military, of a type in which a pressure-sensitive detection device (5) is mobile between a first position that it takes when said device is under the effect of atmospheric pressure and a second position at which priming takes place, said device including switch component (4) for the pyrotechnical chain (42, 43, 45) which in a first safety position locking said detection device when not in its second position forms a screen across said pyrotechnical chain and when in a second arming position that it acquires when said detection device reaches its second position releases said pyrotechnical chain with the switch component of this chain free to move from its second position to a third, neutral position, while said detection device returns from its second position to its first position, with said pyrotechnical switch component again acting as a screen across the pyrotechnical chain in its third position, device characterized by the fact that it is arranged such that the switch component of said chain cannot be released from this third position unless done so manually, regardless of any later motion of said detection device.

Description

The present invention relates to a security and arming device for priming underwater charges, in particular military charges, and more particularly such a device of the type in which a pressure-sensitive detection member is movable between a first position that 'it adopts when the device is substantially at atmospheric pressure and a second position which it adopts when the device has reached a pressure from which the priming can be carried out.

Such devices are for example used in destruction charges or underwater mines. French Patent No. 2,330,512 also describes a device of this type applied to a pyrotechnic shear intended to cut submerged orins. These known devices have a number of drawbacks.

First of all, the arming, that is to say the passage from the SECURITY position to the ARM position, is progressive. The arming is indeed often caused by the depression of a hydrostatic piston sensitive to the external pressure and consequently to the depth. This hydrostatic piston plays the role of both an arming detector and an arming engine, and even possibly that of a pyrotechnic chain switch. As a result, the pyrotechnic chain switch leaves the SAFETY position from the first request to progressively go to the ARM position. During the passage from one position to the other one cannot know with certainty if the pyrotechnic chain switch still plays its role so that safety is no longer guaranteed from the start of the movement.

Furthermore, when these devices have been activated, that is to say when they have moved to the WEAPON position, they can no longer return to the SAFETY position, which has serious drawbacks in a certain number of cases.

So in case of failure of operation and whatever the origin of the failure the device remains armed. It is therefore dangerous and its neutralization can often only be done by destruction.

These drawbacks are partially avoided in the device for initiating underwater charges described in patent FR 2 131 757, and comprising an arming detection piston, pressure sensitive and movable between two positicns (corresponding to atmospheric pressure and immersion), a pyrotechnic chain interrupting member released by the detection member from a first safety position where it screens across the pyrotechnic chain to a second cocking position.

However, the screen cannot be irreversibly moved to a third sterilization position forming a pyrotechnic chain screen when the detection member returns to its initial position, the release of this third sterilization position not having to be carried out. , for safety reasons only by external intervention, despite any subsequent movement of the detection member. Indeed, after a return to atmospheric pressure, the displacement of the screen is not irreversible, since if the piston is again subjected to immersion, the switch member resumes movement towards its "armed" position . We therefore see the major drawback of this embodiment which does not allow, in the event of an accidental rise of the system after its activation, a final and irreversible sterilization, except external intervention.

This system can be brought to operate under conditions other than those foreseen therefore dangerous.

On the other hand, nothing indicates with certainty, on the known devices, the position, or even the possible absence of the pyrotechnic chain switch.

This absence of indication is particularly troublesome and dangerous when assembling the safety and arming device on the load, when handling the assembly, checking, dismantling or recovering.

The present invention aims to overcome these drawbacks.

For this purpose it relates to a security and arming device for the initiation of underwater charges, in particular military, of the type in which a detection member, sensitive to pressure, is movable between a first position that it adopts when the device is substantially at atmospheric pressure and a second position which it adopts when the device has reached a pressure from which priming can take place, device comprising a pyrotechnic chain interrupting member which, in a first safety position where it is locked by the detection member when the latter is not in its second position, forms a screen across the pyrotechnic chain and, in a second arming position which it adopts when the the detection member reaches its second position releases the pyrotechnic chain, device characterized in that the pyrotechnic chain switch member is arranged to move from its second position to a t third sterilization position when the detection member moves back from its second position to its first position, the pyrotechnic chain switch member forming again in its third screen position across the pyrotechnic chain and cannot be released from this third position without intervention outside despite any subsequent movement of the detection member.

Consequently, in the event of an accidental ascent of the system, the device does not remain armed, contrary to what was the case until now. On the contrary, it finds itself neutralized in the STERILIZATION position from where it can only be brought back to the SECURITY position or to the WEAPON position after voluntary intervention.

It is therefore not necessary in this case to destroy the device and the load which it accompanies which is of obvious interest from an economic point of view and allows a posteriori the analysis of the incident and avoids damage to the environment and in particular the installation device.

In a preferred embodiment of the invention, the device comprises a timepiece mechanism capable of being triggered when the pyrotechnic chain switch member moves from its first to its second position and the pyrotechnic chain switch member is designed to be move from its second position to a fourth sterilization position after a certain period of time counted down by the clock mechanism, the pyrotechnic chain switch member forming again in its fourth screen position across the pyrotechnic chain and cannot be released from this fourth position without external intervention despite any subsequent movement of the detection device.

It is therefore considered that after a certain time chosen after arming the device, its non-operation results from a failure. The device and the load are therefore neutralized whatever the origin of the misfire with the same advantages as sterilization in the event of a rise.

Advantageously, the fourth position of the pyrotechnic chain switch member is merged with its third position.

Also in a preferred embodiment of the invention, the device comprises means for making the position of the pyrotechnic chain switch member visible from the outside.

The pyrotechnic chain switch member may for example comprise a rotor disposed between a primer and the rest of the pyrotechnic chain, this rotor having a hole coming to be placed in front of the primer in the second position of the rotor.

This hole can be left empty or contain a relay of explosive transmission. The priming of the charge is possible when the hole is placed between the primer and the rest of the pyrotechnic chain, therefore in the second position of the rotor, but is however not possible when the rotor shields in its other positions.

In addition, the detection member advantageously comprises a hydrostatic piston movable axially as a function of the external pressure, this piston comprising a section of reduced diameter, and a ball prevents the rotation of the rotor by remaining blocked in a notch of this rotor by a generator. of the piston when the latter is not in its second position, said ball allowing the rotation of the rotor when the reduced diameter section of the piston is opposite the ball when the piston is in its second position.

The reduced diameter section of the piston is disposed on this piston at a height such that, when the piston is pressed under the effect of pressure, it reaches the level of the ball when the device has reached the cocking depth . At this instant the ball consequently unlocks the rotor which passes from its SAFETY position to its ARMED position.

The device may also include angular locking means of the rotor in its second position, these locking means comprising a stop integral in rotation with the rotor and axially movable and means cooperating with this stop, the detection member being arranged to bring the stopper in an axial position in which it is likely to come into contact with the cooperating means when it detects a pressure greater than a predetermined value and to axially move the stopper from the cooperating means when the pressure again becomes lower than this predetermined value.

Therefore after arming the device it remains in the ARMED position as long as the pressure is greater than the arming value. If the pressure becomes lower again, that is to say in the event of an ascent, the device is released and can therefore leave the ARMED position.

In order to ensure the sterilization of the device in the event of non-operation, it advantageously comprises a clockwork mechanism provided with an output shaft on which is mounted a first cam capable of cooperating with a stopper integral in rotation with the rotor, this first cam being arranged to block the rotor in its second position by being in contact with the stop for a predetermined time after the triggering of the timepiece mechanism and to release the rotor by disappearing from the path of the stop after this predetermined time.

A second cam can also be mounted on the output shaft of the clock mechanism, this cam being capable of cooperating with a stop controlled by the rotation of the rotor to prevent movement of the clock mechanism when the rotor is in its first position and to allow this movement when the rotor leaves this first position.

The clockwork mechanism is therefore triggered at the instant when the device changes from its SAFETY position to its ARMED position and counts down from this moment the time after which the load must be considered as not having worked.

To ensure the sterilization of the device in the event of non-operation or in the event of a rise, the device advantageously comprises elastic means for bringing the rotor to a third angular position when, while it is in its second position, the rotor stop is released.

The rotor then preferably comprises a lock capable of engaging under the effect of an elastic means in a hole formed in a fixed member of the device when the rotor is in its third position.

The device according to the invention may also comprise a window through which are visible areas of the rotor identified differently, for example by colors, depending on the position of the rotor.

This window can for example be mounted outside the hole mentioned above, the identification area of the third position of the rotor being provided by the end of the lock.

The device according to the invention can also further comprise electrical safety devices comprising at least one microswitch making the circuits active in the second position of the pyrotechnic chain switch member and inactive in its other positions.

In this case the microswitches can for example be arranged so that their actuating members cooperate with flats formed on a cylindrical part of the rotor to open or close the microswitches depending on the position rotor angle.

• la figure 1 est une vue en élévation en coupe d'un dispositif de sécurité et d'armement selon l'invention,
• la figure 2 est une vue selon la flèche F2 de la figure 1,
• la figure 3 est une vue en coupe selon la ligne III-III de la figure 1,
• la figure 4 est une vue selon la flèche F4 de la figure 3 après que le mécanisme horloger ait été enlevé,
• la figure 5 est une vue partielle en coupe selon la ligne V-V de la figure 3,
• la figure 6 est une vue en coupe du rotor selon la ligne VI-VI de la la figure 3,
• les figures 7a, 7b et 7c sont des vues très simplifiées représentant dans différentes positions relatives la butée du rotor et la came du mouvement horloger,
• les figures 8a, 8b et 8c représentent partiellement le dispositif vu de l'arrière de la figure 3 avec le rotor dans trois positions différentes,
• les figures 9a, 9b, et 9c sont des vues en coupe selon les lignes IX-IX des figures 8a, 8b et 8c respectivement et,
• les figures 10a, 10b et 10c sont des vues en coupe selon les lignes X-X des figures 8a, 8b et 8c respectivement.

A particular embodiment will now be described by way of nonlimiting example with reference to the appended schematic drawings in which:

• FIG. 1 is a sectional elevation view of a security and arming device according to the invention,
• FIG. 2 is a view along the arrow F2 in FIG. 1,
• FIG. 3 is a sectional view along line III-III of FIG. 1,
• FIG. 4 is a view along arrow F4 in FIG. 3 after the clock mechanism has been removed,
• FIG. 5 is a partial sectional view along the line VV in FIG. 3,
• FIG. 6 is a sectional view of the rotor along the line VI-VI of FIG. 3,
• FIGS. 7a, 7b and 7c are very simplified views showing in different relative positions the stop of the rotor and the cam of the watch movement,
• FIGS. 8a, 8b and 8c partially represent the device seen from the rear of FIG. 3 with the rotor in three different positions,
• FIGS. 9a, 9b, and 9c are sectional views along lines IX-IX of FIGS. 8a, 8b and 8c respectively and,
• Figures 10a, 10b and 10c are sectional views along lines XX of Figures 8a, 8b and 8c respectively.

As shown in the drawings, the device generally comprises a housing 1 inside which is mounted a support member 2 and a cylinder 3. The support member 2 rotatably supports a rotor 4 whose axis of rotation is perpendicular to the axis of cylinder 3 and in cylinder 3 is slidably mounted a hydrostatic piston 5.

The piston 5 has its head 6 subjected to external pressure through an orifice 7 in the housing. A membrane 8 held by the head of the piston seals between the outside and the inside of the device while allowing the longitudinal movements of the piston.

A pin 9 whose function will be described below is accessible from the outside and in the position where it is shown in FIG. 3 it prevents the movement of the piston 5.

A helical calibration spring 10 disposed at the bottom of the cylinder 3 tends to cause the piston 5 to come out of the cylinder until a flange 11 of the piston abuts on an annular projection 12 provided on the interior surface of the cylinder 3.

The body of the piston 5 also comprises a section 13 of reduced diameter at its upper part and another part 14 of smaller diameter towards its lower part.

The rotor 4 is essentially formed by a flywheel 15 and a shaft 16.

At the end of the shaft 16 opposite the flywheel 15 is fixed one end of a spiral spring 17 the other end of which is wedged in the housing as shown in FIG. 1. The spring 17 is constrained so as to tend to rotate the rotor 4 in the direction of arrow A in figure 2.

A hole 18 is drilled in the flywheel 15 parallel to the axis of the rotor 4 and in this hole 18 is placed an explosive transmission relay 19.

Another hole 20 is formed at the periphery of the flywheel 15 perpendicular to the axis of the rotor 4. A latch 21 is placed in the hole 20 this latch being hollow in order to receive a helical spring 22 which also bears on the bottom of the hole 20 to tend to release the lock 21 from the hole 20. The lock 21 is however held in the hole 20 by the surface of the support member 2. The member 2 however has a hole 23 in which the lock can come out 21 as will be described below.

The rotor 4 also has an axial bore 24. In this bore is placed a rod 25 whose outer end is rounded in the shape of a half-sphere and whose inner end is pushed back by a helical spring 26 bearing against the bottom of the drilling 24.

As shown in FIG. 6, a finger 27 projects from the rod 25 through the shaft 16 and preferably carries at its end a ball bearing 28 for reasons which will be explained below.

The shaft 16 also carries a screw 29, the head of which projects so that it can serve as a stop.

The shaft 16 also has flats 30 shown in Figure 5 capable of cooperating with the actuating members 31 of microswitches 32 mounted on the device housing.

The microswitches 32 provide various electrical safety features by short-circuiting the ignition capacitors and also allow an electronic firing timer to be triggered. However, the electronic part of the device which is not part of the invention will not be described in more detail.

The flywheel 15 of the rotor 4 finally has on its periphery on the one hand a circular notch 33 and on the other hand a groove 34 on a quarter of its periphery.

The cylinder 3 for its part comprises, at the level of the notch 33 and the groove 34, a bore 35 and a ball 36 can find a place both in the bore ₃₅ and in the notch 33 or in the bore 35 and the groove 34 being held by a generator of the piston 5.

The device also includes a clock mechanism 37 of any known type, the output shaft of which supports a first cam 38 and a second cam 39.

As shown in FIG. 4, the cam 39 has an inclined face 40 capable of cooperating with a lever 41 rotatably mounted on the housing 2. The lever 41 can come into abutment on the head of the screw 29.

The cam 38 is in the form of a segment of a circle and is arranged to cooperate with the bearing 28 which can roll on its surface as shown in FIGS. 7a to 7c.

The support member 2 also receives, as shown in FIG. 1, a primer holder 42 on which is mounted a primer 43 which can be ignited by the wires 44 coming from the electronic timer not shown.

The primer 43 is located at the same distance from the axis of the rotor 4 as the orifice 18.

On the other side of the rotor is located a detonation relay 45 in contact with the active charge 46.

The housing 1 also has an opening 47 in the extension of the hole 23 in the support member 2 and this opening 47 is closed by a window 48.

Finally, a pin 49 is mounted on the support member 2 at such a distance from the axis of the rotor 4 that it can act as a stop for the head of the screw 29.

The device is shown in Figures 1 to 6, 8a, 9a and 10a in its SECURITY position.

The hydrostatic piston is held in its upper position by the pin 9.

In this position, the rotor 4 is locked in rotation by the ball 36 which is held in the notch 33 by the generator of the piston 5.

The head of the screw 29 keeps the lever pressed on the inclined face 40 of the cam 39, thus preventing the movement of the watch mechanism 37.

As shown in FIG. 1, the flywheel 15 of the rotor 4 forms a screen between the primer 43 and the detonation relay 45, thus preventing any untimely priming of the device.

In addition, the microswitches 32 have their actuating members 31 in the high position because they are then supported on one of the flats of the shaft 16. They then short-circuit the firing circuits.

After fitting the device, the pin 9 is removed so that if the pressure indicates that the depth reached is sufficient, the hydrostatic piston 5 sinks into the cylinder 3.

The rod 25 which was previously in the reduced diameter zone 14 of the piston 5 is then pressed in the direction of the arrow B in FIG. 8a.

In addition, the section 13 of reduced diameter of the piston 5 comes opposite the ball 36 which is thus no longer held in the notch 33 and consequently frees the rotor 4 in rotation.

Driven by the spring 17, the latter consequently rotates in the direction of the arrow A in FIG. 2 until the ball bearing 28 comes into abutment on the cam 38. In addition due to the rotation of the rotor 4 the head of the screw 29 disappears in the direction of the arrow C in FIG. 4, thus allowing the lever 41 to be released in the direction of the arrow D, which releases the cam 39 and therefore allows the clock mechanism 37 to start.

In addition, the actuating members 31 of the microswitches 32 are pressed in because the shaft 16 has made a quarter turn, which has the effect of activating the firing circuit and in particular of starting the firing timer. fire.

In this position the transmission relay 19 is aligned with the primer 43 and the detonation relay 45 so that firing can take place.

We note first of all that in the event of a rise in the dis positive the piston 5 will move in the cylinder 3 until it returns to the position of FIG. 3. The part 14 of reduced diameter then returns opposite the rod 25 which then moves under the effect of the spring 26 in the direction of arrow E in Figure 8b.

The ball bearing 28 is then released from the cam 29 and the rotor 4 resumes its rotation in the direction of the arrow A in FIG. 2 under the action of the spring 17. This rotation is possible despite the rise of the piston 5 due to the fact that the ball 36 is then in the groove 34. The rotational movement of the rotor 4 is stopped when the head of the screw 29 abuts on the pin 49 after a quarter-turn rotation is ie after a half-turn rotation from the SAFETY position.

In this STERILIZATION position, it is noted first of all that the microswitches return to the safety position because the actuating members 31 are in contact with the second flat 30 of the shaft 16. In addition, the transmission relay is no longer between the primer 43 and the detonation relay so that any firing of the device is impossible. Finally, the rotor having made a U-turn relative to its position in FIG. 3, the bolt 21 is opposite the hole 23 in which it engages under the action of the spring 22. Then being both in the hole 20 of the rotor 4 and in the hole 23 of the support member 2 it prevents any subsequent movement of the rotor 4 which cannot thus return to the READY position without dismantling.

It has already been mentioned that when switching to the ARM position the electronic firing timer as well as the clock mechanism 37 are triggered. For example, the electronic timer is set to ignite the system after a period of 20 minutes.

During this period the cam 38 which is initially in the position shown in FIGS. 7a and 10b begins to rotate in the direction of the arrow F in FIG. 7a. It is for example at the end of the time provided for the ignition in the position of Figure 7b.

If for any reason this firing does not take place the cam 38 continues its rotation as indicated by the arrow G in FIG. 7b until it is in the position shown in Figures 7c and 10c for example after a period of 40 minutes.

In this position the cam disappears from the front of the ball bearing 28 and thus releases the rotor 4.

Driven by the spring 17, the latter therefore begins to rotate in the direction of the arrow H in FIG. 7c and of the arrow I in FIG. 9c.

This movement continues for a quarter of a turn to the STERILIZATION position as described above in the case of an ascent of the device.

As previously also, the rotor 4 is locked in the STERILIZATION position where it forms a screen between the initiation 43 and the detonation relay 45 and the microswitches 32 are returned to the safety position.

In order to allow the display of the state of the device, it is possible to provide a mark, for example green, in the area 50 of the steering wheel 15, this mark being visible by the window 48 when the device is in the SAFETY position.

Another mark, for example red, is provided in the zone 51 which is located in front of the window 48 when the device is in the ARMED position.

Finally, a third mark, for example yellow, is provided at the upper part of the lock 21 to indicate through the window 48 that the device is in the STERILIZATION position.

As it goes without saying, the invention is not limited to the embodiment described above to which various variants and modifications can be made without departing from its scope or its spirit.

Claims (15)

1. Security and arming device for the initiation of underwater charges, in particular military charges, of the type in which a detection member (5). pressure sensitive is movable between a first position which it adopts when the device is substantially at atmospheric pressure and a second position from which priming can take place, device comprising a pyrotechnic chain switch member (4) (42,43,45) which, in a first safety position where it is locked by the detection member when the latter is not in its second position, forms a screen across the pyrotechnic chain, and, in a second arming position which it adopts when the detection member reaches its second position, releases the pyrotechnic chain, device characterized in that the pyrotechnic chain switch member is arranged to move from its second position to a third sterilization position when the detection member moves back from its second position to its first position, the pyrotechnic chain switch member forming again, in its trio isth position, screen across the pyrotechnic chain, and cannot be released from this third position without external intervention, despite any subsequent movement of the detection member. 2. Device according to claim 1, characterized in that it comprises a timepiece mechanism (37), capable of being triggered when the pyrotechnic chain switch member moves from its first to its second position, and in that the the pyrotechnic chain switch member is arranged to move from its second position to a fourth sterilization position after a certain period of time counted down by the clockwork mechanism, the pyrotechnic chain switch member again forming, in its fourth position, a cross screen of the pyrotechnic chain, and being unable to be released from this fourth position without external intervention, despite any subsequent movement of the detection member. 3. Device according to all of claims 1 and 2, characterized in that the fourth position of the pyrotechnic chain switch member is merged with its third position. 4. Device according to any one of claims 1 to ₃ , characterized in that it comprises means for making visible from its exterior the position of the pyrotechnic chain switch member. ₅ . Device according to any one of Claims 1 to 4, characterized in that the pyrotechnic chain interrupting member comprises a rotor arranged between a primer and the rest of the pyrotechnic chain, this rotor comprising a hole placed in front of the primer in the second position of the rotor. 6. Device according to claim 5, characterized in that the detection member comprises a hydrostatic piston movable axially as a function of the external pressure, this piston comprising a section of reduced diameter, and that a ball prevents rotation of the rotor while remaining locked in a notch of this rotor by a generator of the piston when the latter is not in its second position, said ball allowing the rotation of the rotor when the reduced diameter section of the piston is opposite the ball when the piston is in its second position. ₇ . Device according to any one of claims ₅ and 6, characterized in that it comprises means for angular locking of the rotor in its second position, these locking means comprise a stop integral with the rotation of the rotor and axially movable, and means cooperating with this stop, and that the detection member is arranged to bring the stop in an axial position in which it is likely to come into contact with the cooperating means when it detects a pressure greater than a predetermined value, and for axially deviate the abutment from the cooperating means when the pressure again becomes lower than this predetermined value. ₈ . Device according to any one of Claims ₅ to ₇ , characterized in that it comprises a clockwork mechanism provided with an output shaft on which is mounted a first cam capable of cooperating with a stop integral with the rotation of the rotor, and that this first cam is arranged to lock the rotor in its second position by being in contact with the stop for a predetermined time after the trigger of the clockwork mechanism, and to release the rotor by disappearing from the path of the stop after this predetermined time. 9. Device according to claim ₈ , characterized in that a second cam is mounted on the output shaft of the clockwork mechanism, this cam being capable of cooperating with a stop controlled by the rotation of the rotor to prevent movement of the mechanism watchmaker when the rotor is in its first position and to allow this movement when the rotor leaves this first position. ₁₀ . Device according to any one of Claims ₇ to 9, characterized in that it comprises elastic means for bringing the rotor to a third angular position when, while it is in its second position, the rotor stop is released . 11. Device according to any one of claims 5 to lo, characterized in that the rotor comprises a lock capable of engaging, under the effect of an elastic means, in a hole formed in a fixed member of the device when the rotor is in its third position. 12. Device according to any one of claims 5 to 11, characterized in that it comprises a window through which are visible rotor areas identified differently, for example by colors, depending on the position of the rotor. ₁₃ . Device according to all of claims 11 and 12, characterized in that the window is mounted outside of said hole, and that the identification zone of the third position of the rotor is formed by the end of the lock. ₁₄ . Device according to any one of Claims 1 to ₃ ', characterized in that it furthermore comprises electrical safety devices comprising at least one microswitch making the electrical circuits active in the second position of the pyrotechnic chain switch member and inactive in its other positions. ₁₅ . Device according to all of claims ₅ and 4, characterized in that the microswitches are arranged so that their actuating members cooperate with flats formed on a cylindrical part of the rotor to open or close the microswitches depending on the angular position of the rotor.

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