Device for venting an explosive charge and munition equipped with such a device

Abstract

A venting device for a projectile includes a first part comprising a body containing an explosive charge and a second part comprising an actuating element for triggering the explosive charge, the first and second parts forming an assembly able to confine the explosive charge when they are connected, the venting device comprising: a sealing means configured to render the projectile gastight and fluidtight when the first and second parts are connected; an opening means able to allow the projectile to open, the opening means being able to be triggered when the internal pressure in the projectile is higher than or equal to a given pressure threshold; a pushing means able to enlarge the opening of the projectile once the opening means has been triggered.

Claims

1. A venting device for venting an explosive charge for a projectile comprising a first part comprising a body containing an explosive charge and a second part comprising an actuating element for triggering said explosive charge, the first and second parts of said projectile forming an assembly able to confine the explosive charge when said first and second parts of said projectile are connected, said venting device comprising: a sealing means configured to render the projectile gastight and fluidtight when the first and second parts of the projectile are connected; an opening means able to allow the projectile to open in order to create an opening in the projectile, said opening means being able to be triggered when an internal pressure of the projectile is higher than or equal to a given pressure threshold; a pushing means able to enlarge the opening of the projectile once the opening means has been triggered.

2. The venting device according to claim 1, configured in such a way as to allow an opening between the first part and the second part of the projectile.

3. The venting device according to claim 2, the opening means being located between the first part and the second part of the projectile.

4. The venting device according to claim 1, the body comprising a first part and a second part, and the venting device being configured in such a way as to allow the opening to form in the body between said first part of the body and said second part of the body.

5. The venting device according to claim 4, the opening means being located between the first part of the body and the second part of the body.

6. The venting device according to claim 1, the opening means comprising a mechanical component able to break when an internal pressure is higher than or equal to the given pressure threshold.

7. The venting device according to claim 6, wherein the opening means comprises a threaded component having a screw thread able to strip when the internal pressure of the projectile is higher than or equal to the given pressure threshold.

8. The venting device according to claim 1, the pushing means comprising a compressed spring able to relax once the opening means has been triggered.

9. The venting device according to claim 1, the sealing means comprising at least one seal.

10. The venting device according to claim 1, further comprising a first component connected to the first part of the projectile and located between said first part of the projectile and the second part of the projectile, the sealing means and the pushing means being located between said first component and said second part of the projectile.

11. The venting device according to claim 10, the sealing means being located on the first component or on the second component.

12. The venting device according to claim 10, the pushing means being connected to the first component or to the second component.

13. The venting device according to claim 10, the opening means being located between the first part of the projectile and the second part of the projectile, and the opening means being connected to the first component or to the second component.

14. The venting device according to claim 1, further comprising a second component, connected to the second part of the projectile and located between the first part of the projectile and said second part of the projectile, the sealing means and the pushing means being located between said second component and said first part of the projectile, or between said second component and said first component.

15. A munition comprising a projectile equipped with a venting device according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention will become apparent from the following description given by way of nonlimiting illustration and made with reference to the attached figures among which:

(2) FIG. 1 depicts the projectile part of a munition according to the prior art.

(3) FIG. 2 depicts a first example of a device according to the invention, seen in the closed configuration.

(4) FIG. 3 depicts the first example of a device according to the invention, seen in the open configuration.

(5) FIG. 4 depicts a detail of the first example of a device according to the invention.

(6) FIG. 5 depicts a second example of a device according to the invention, seen in the closed configuration.

(7) FIG. 6 depicts the second example of a device according to the invention, seen in the open configuration.

(8) FIG. 7 depicts a third example of a device according to the invention, seen in the closed configuration.

(9) FIG. 8 depicts the third example of a device according to the invention, seen in the open configuration.

(10) FIG. 9 depicts a fourth example of a device according to the invention, seen in the closed configuration.

(11) FIG. 10 depicts the fourth example of a device according to the invention, seen in the open configuration.

DETAILED DESCRIPTION

(12) FIG. 1 was described in the Prior art section of the present description and will not be revisited here.

(13) FIGS. 2, 3 and 4 depict a first example of a venting device 4 according to the invention, seen in the closed configuration (device not triggered) and in the open configuration (device triggered). They readopt the same numerical references as FIG. 1 for elements that are in common with FIG. 1.

(14) FIGS. 2, 3 and 4 illustrate a projectile element 1 for a munition. The propulsive element of the munition has not been depicted in the figures. The projectile element 1 is an element that is elongate in the longitudinal direction X and exhibits symmetry with respect to said longitudinal direction.

(15) The projectile element 1 comprises a first part 2 containing the explosive charge 21 and a second part 3 comprising an actuating element for triggering the explosive charge. In FIG. 2, the first and second parts are depicted as solidly joined together (in the so-called closed configuration). In FIG. 3, the first and second parts are depicted as disconnected (the so-called open configuration).

(16) The first part 2 comprises a munition body 22, also referred to as body, delimiting an internal cavity containing the explosive charge 21. According to this first exemplary embodiment, the body 22 is made as a single part. The body may have a thickness of between a few millimeters to a few centimeters. As illustrated, the body 22 has an open end 22a situated facing the second part 3, its opposite end 22b being closed.

(17) In the example illustrated, the second part comprises an initiating relay 31 located between the second part and the first part.

(18) The first part may be referred to for the sake of simplicity as the warhead body.

(19) The second part may be referred to as the detonation fuze or, for the sake of simplicity, as the fuze.

(20) The fuze is depicted schematically here. Thus, conventionally, the fuze may comprise, in addition to an initiation chain, electronic or mechanical means that ensure its operation, a safety device, and means for initiating the initiation chain.

(21) When the first and second parts are assembled, they form the projectile 1 which is a closed assembly. In other words, the fuze closes the munition body 22, closing off its open end 22a, thus confining the explosive charge 21.

(22) According to the first exemplary embodiment shown, the venting system 4 is located between the fuze 3 and the warhead body 2. Said venting system makes it possible to form a connection between said fuze and said warhead body (when the system has not been triggered), or to break said connection (when the system is triggered). When the connection is broken, that is to say when the venting system is triggered, the fuze and the warhead body are disconnected.

(23) The venting system depicted comprises several elements: a first component 41, which can be referred to as the first confinement cup or first cup in the present invention: said first component may serve as a bearing surface for the pushing means 45 and may also serve to protect the explosive charge 21 from mechanical impacts; in the example illustrated, the first confinement cup 41 is configured to cover the end 2a of the warhead body that faces the fuze 3; it is connected to the body 22, for example by screwing.
a second component 42, which may be referred to as the second confinement cup or second cup in the present invention: said second component is configured in such a way as to cover all or part of the end 3a of the fuze that faces the warhead body 2, and is thus able to contain the initiation relay 31; it is connected to the fuze 3, for example by a screw-fastening system 46;
an opening means 43, which may be referred to as the venting ring in the present invention, able to allow an opening between the fuze and the warhead body, more specifically in the example illustrated between the second confinement cup 42 and the warhead body 2; the venting ring depicted is a threaded ring positioned on the second cup 42, the screw thread 431 of which being formed on its external surface. Said screw thread is intended to collaborate with a tapped thread 221 formed on an internal surface of the open end 22a of the munition body 22. The connection between the screw thread 431 and the tapped thread 221 makes it possible to form a connection between the fuze 3 and the warhead body 2. The screw thread 431 is configured to break when the internal pressure reaches a defined pressure threshold. More specifically, the screw thread strips under the effect of the thrust formed by the pressure. This then has the effect of breaking the connection between the fuze and the warhead body;
a sealing means 44, formed in the example illustrated by a circular seal system located in a groove 42a situated on an external circumference of the second confinement cup 42 facing the first confinement cup 41 (or alternatively, facing the body 22 for example if there is no first cup): the sealing means makes it possible to ensure that the pressure increases, preferably rapidly, in the projectile under the effect of the change in phase of the explosive charge (liquid or gas) until the threshold pressure able to trigger the venting ring 43 is reached;
a rapid pushing means 45, which is represented by a compressed spring located between the fuze 3 and the warhead body 2 and, more specifically in the example illustrated, between the first cup 41 and the second cup 42 (alternatively, the spring may be located between the second cup 42 and the body 22): when the venting ring 43 is triggered, the connection between the fuze 3 and the warhead body 2 is broken and the pushing means 45 allows these to be completely disconnected notably by overcoming the friction force of the stripped screw thread 431, of the seal system 44 and by exerting a force on the mass of the part that is to be pushed. This allows the connection between the fuze and the explosive charge to be opened up completely and makes it possible to ensure sufficient separation between said fuze and said explosive charge. This notably makes it possible to ensure the venting of the explosive.

(24) Alternatively, the bearing surface of the pushing means 45 may be formed directly by an internal surface of the open end 22a of the munition body 22, without the need to fit a first cup.

(25) In the example depicted, the venting ring is positioned on the second cup. Alternatively, it may be positioned on the first cup. As a further alternative, the venting ring may be positioned directly at the end 3a of the fuze that faces the warhead body 2, without there being a need to fit a first cup and/or a second cup.

(26) The person skilled in the art will know how to calculate the characteristics of the spring in order notably to overcome the friction force of the stripped screw thread, of the seal system, and in order to exert a force on the mass of the part that is to be pushed.

(27) Furthermore, the person skilled in the art will know how to determine the minimum separation distance to be obtained between the fuze and the explosive charge when the venting device is triggered. This minimum separation distance is notably dependent on the sensitivity of the explosive charge.

(28) In place of a compression spring, the pushing means may be a blade 47 or a component made of shape memory material capable of expanding under the effect of temperature and, in general, any means able to create a rapid pushing force between two bodies (as illustrated in FIGS. 7-8). According to one alternative embodiment, of the first and the second cups 41, 42 one may have shape memory and thus fulfill the function of rapid pushing in place of a spring (as illustrated in FIGS. 9-10).

(29) In place of a threaded venting ring, the opening means may be a component, such as a shear pin, able to be sheared at the defined pressure, or a bonded or welded joint engineered to withstand up to the defined pressure, or else a component a weakened part of which is engineered to withstand up to the defined pressure.

(30) FIGS. 5 and 6 illustrate a second exemplary embodiment of a venting device 4 for a projectile 1. FIG. 5 depicts a projectile 1 in the closed configuration (with the device not triggered). FIG. 6 depicts the projectile 1 in the open configuration (device triggered).

(31) The second example differs from the first example in that the opening is generated on the body which separates into two parts and in that the opening means 43, or venting ring, is not located between the fuze and the warhead body, but is positioned at the level of the body 22, the body comprising a first part 221 located facing the fuze 3 and a second part 222 located in the opposite direction from said fuze. The other elements described in connection with FIGS. 2 to 4 are unchanged, as the alternative forms of embodiment may equally apply to the second example.

(32) When the venting device has not been triggered (FIG. 5), the explosive is confined inside the body 22 closed by the fuze 3 at the level of its open end 22a, and the first and second parts 221 and 222 of the body are assembled in a sealed manner.

(33) When the venting device is triggered (FIG. 6), the body 22 is opened between the first and second parts 221 and 222 by virtue of the opening means 43 and the spring 45 located between the fuze 3 and the warhead body 2 acts almost instantly, pushing the second part 222 and carrying with it the explosive charge 21. This makes it possible to ensure a sufficient separation distance between said explosive charge and the fuze 3.

(34) Thus, the opening in the projectile is created not between the fuze and the body but at the level of the body, which separates into two disconnected parts.

(35) According to the second embodiment, the pushing means 45 is, as in the first embodiment, located between the fuze and the warhead body.

(36) Alternatively, the pushing means may be located between the first or second parts of the body, or at any other point in the projectile suited to performing the same separating function.

(37) According to the second embodiment, the sealing means 44 is located between the fuze and the warhead body.

(38) Furthermore, another sealing means may be located between the first and second parts of the body (this is not depicted in the figures).

(39) The following advantages become apparent from the embodiments described and from the invention in general.

(40) The invention makes it possible to obtain rapid and significantly extensive venting, and this makes it possible in a timely manner to limit the overpressure phase of the explosive charge. Specifically, once the opening is formed when the opening means is triggered (or in other words, once the mechanical-fuse system has been triggered), the pushing system takes over and significantly enlarges the opening in the projectile independently of the state of the explosive charge. In other words, there is no longer a need for a pressure (gas pressure in the case of a burn, or hydraulic pressure in the event of the explosive melting) to be maintained.

(41) The opening of the projectile is governed by the overpressure and not by the temperature, ensuring the integrity of the mechanical elements. Pressure control according to the invention also means that the maximum temperature attained by the projectile can be significantly below the cookoff temperature of the explosive charge.

(42) Distancing the fuze and the explosive charge (or the most-part of the explosive charge) from one another allows the explosive charge to be distanced from the detonation system.

(43) The venting device can be configured so that the fuze or the explosive charge is completely ejected from the projectile. Whether it is the fuze or the explosive charge that is able to be ejected, this notably makes it possible to avoid unwanted initiation of the explosive charge following undesired initiation of the initiation chain.

(44) Furthermore, the opening of the projectile as permitted by the invention makes it possible to ensure a sufficiently high rate of escape of the gases notably associated with the cookoff phenomena in order to avoid runaway in the burning of the explosive and deflagration of said explosive.

(45) In so doing, the invention guarantees a type-V or type-VI response to thermal attack.

(46) The present invention is not restricted to the embodiment previously described but extends to any alternative form or to any embodiment that falls within the scope of the claims.