EP0518711B1 - Mine with sensor wires - Google Patents

Description

The present invention relates to a mine with trap wires of the type comprising a hollow body in which are housed several trap wires wound each on a reel, and an automatic wire ejection system comprising a device for releasing an opening in a wall of the body of the mine, a projectile attached to a free end of each trap wire and means for ejecting the projectiles through the opening of the body of the mine with concomitant unwinding of the wires wound on the coils.

A mine of the aforementioned type is generally released from a vector such as a shell, and it generally has two parallel flat faces connected by a cylindrical wall, so as to come to lie flat on the ground by one of its two faces after drop.

Once the mine is immobilized on the ground, the trap wires are ejected to make it operational, that is to say in condition to detonate if a foreign body comes into contact or strike one of the trap wires, in a way known per se.

A mine of the aforementioned type is described in particular in document DE-37 13424 on which the preamble of independent claim 1 is based, where the opening through which the projectiles are ejected consists of a plurality of openings provided on the side wall cylindrical of the mine body. Each opening opens into a housing in which the trap wire, the projectile and the system for ejecting this projectile consisting of at least one spring placed in compression are mounted. Each opening is closed by a flap mounted at the end of a pivoting arm urged by a spring to tilt outwards from the body of the mine in order to clear the opening and cause the projectile to be ejected by the relaxation of its associated spring. The set of arms is retained by a ring attached around the body of the mine so that the flaps are kept in a closed position. Once the mine is immobilized on the ground, the ring is automatically cut to free the arms.

In document EP-0 389 852 which describes a mine of the type described in the aforementioned document, the coil which itself forms the projectile and its ejection system constituted by a pyrotechnic charge are integral with the flap. In this case, the flipping of the flaps makes it possible to release each coil and its ejection system from the mine body before initiation thereof.

In document DE-A-3 938 119, a mine is described equipped with a plurality of detectors which are activated by a wire connected to each of them. Each detector is isolated by a cover closing the opening, which is ejected during the placement of the mine. The cover is fixed to a plate or arm articulated relative to the body of the mine.

In general, the mines described in these previous documents have the disadvantage of involving arm deployment devices located outside the body of the mine and which are therefore vulnerable during handling and storage operations. . In addition, after dropping and immobilizing these mines on the ground, accidents on the ground can possibly hamper the deployment of the arms. Finally, the permanent loading of these arms by springs complicates the structure of these mines and the assembly operations necessary for their manufacture.

The object of the invention is to overcome the drawbacks presented by the ejection systems of the trap wires of these mines while providing other advantages.

To this end, the invention proposes a mine of the aforementioned type which is characterized in that the device for releasing the projectile ejection opening comprises a shearing means housed in the body of the mine for cutting into a wall of that -a part forming a cover with the dimensions of the opening, and a cover ejection device.

Thus, according to the invention, the ejection system of the trap wires is housed entirely inside the body of the mine, the opening necessary for ejection projectiles only being made and released once the mine is immobilized on the ground after its release.

According to another characteristic of the invention, the means for shearing the cover consists of a plate bearing on a flat face of the body of the mine and secured to a mobile assembly controlled to move along an axis perpendicular to the plate and passing through the center of it, this movable assembly constituting the cover ejection device.

According to yet another characteristic of the invention, the movable assembly comprises at least one piston integral with the shear plate which is driven in translation by the pressure of the gases resulting from the initiation of a pyrotechnic charge which is also used to cause projectile ejection.

In one embodiment of the invention, the coils are supported flat on one face of a plate, and the ejection system is carried by a support fixed on the other face of the plate, this support and the delimiting plate a housing in which the mobile equipment and the pyrotechnic charge are mounted, each projectile being mounted in a chamber, advantageously produced in the body of the coil of the associated trap wire, which communicates with the housing of the mobile equipment by a channel liaison.

According to yet another characteristic of the invention, the ejection system is completed by a timing device to delay the ejection of the projectiles relative to the ejection of the cover so that the latter does not constitute an obstacle liable to be hit by projectiles.

In one embodiment of the invention, the timing device is constituted by a socket which closes the connecting channel, this socket being attached around a piston in a telescopic manner, this assembly forming the movable assembly, for to be integral in translation with the piston after cutting the cover in order to open the connection channel for the free passage of gases resulting from the initiation of the pyrotechnic charge.

As a variant, the timing device can consist of a delay or slow combustion pyrotechnic charge placed in the connecting channel and initiated by the pyrotechnic charge. In this case, an additional pyrotechnic charge is at least placed in the connecting channel, this charge initiated by the slow combustion charge supplying the gases for ejecting the projectiles.

Generally, the mine body has two parallel flat faces, one of them serving as a bearing surface on the ground after immobilization of the mine. Also, according to the invention, the mine comprises two sets of coils of trap wires placed respectively in the vicinity of the two flat faces of the body of the mine, as well as two ejection systems respectively associated with the two sets of coils, and at least the ejection system associated with the coils adjacent to the face of the mine not resting on the ground will be initialized, the other ejection system being able to be used to detach the mine from the ground before it explodes.

A mine in accordance with the invention equipped with such ejection systems for trap wires does not have any vulnerable element liable to come into operation unexpectedly or accidentally, and is of simple and inexpensive construction.

• la figure 1 est une vue en coupe transversale d'une mine à fils pièges conforme à l'Invention,
• les figures 2 à 4 sont des demi-vues en coupe transversale pour illustrer les différentes phases d'éjection des fils pièges,
• la figure 5 est une vue agrandie du détail indiqué par la flèche V sur la figure 1,
• la figure 6 est une demi-vue en coupe transversale pour illustrer un second mode de réalisation de l'Invention,
• la figure 7 est une vue de détail agrandie d'une variante du mode de réalisation représenté à la figure 6,
• et la figure 8 est une demi-vue transversale d'un troisième mode de réalisation de l'Invention.

Other advantages, characteristics and details of the invention will emerge from the explanatory description which follows, given with reference to the appended drawings given solely by way of example and in which:

• FIG. 1 is a cross-sectional view of a mine with trap wires according to the invention,
• Figures 2 to 4 are half-views in cross section to illustrate the different phases of ejection of the trap wires,
• FIG. 5 is an enlarged view of the detail indicated by the arrow V in FIG. 1,
• FIG. 6 is a half-view in cross section to illustrate a second embodiment of the invention,
• FIG. 7 is an enlarged detail view of a variant of the embodiment shown in FIG. 6,
• and Figure 8 is a cross-sectional half view of a third embodiment of the invention.

In general, the mine 1 as shown in the figures comprises a hollow body 2 in which are housed all the constituent elements of the mine. This body is of generally cylindrical shape with two parallel flat faces 3 and 4 joined to one another by a cylindrical wall 5.

The mine 1 comprises a plurality of trap wires 6 (FIG. 4) of a certain length, which are each initially wound on a coil housed inside the body 2 of the mine 1. In the example considered here and in referring in particular to Figure 1, the mine 1 comprises two similar sets of coils 8a and 8b mounted on two plates 9a and 9b located in the vicinity of the two faces 3 and 4, and parallel to them, respectively. These two sets of coils 8a and 8b are associated with two ejection systems 10a and 10b of the trap wires 6, respectively. Also, for reasons of symmetry, only the set of coils 8a and the associated ejection system 10a will be described below.

The plate 9a of generally circular shape has on its so-called internal face located on the internal side of the mine, a central recess 12 of axis A extended axially by an opening of smaller diameter which extends beyond the other face said external of the plate 9a by the internal volume of a tubular part forming a sleeve 13 projecting from the external face of the plate 9a. The free end of the sleeve 13 has an internal rim forming a stop 14.

The coils 8a, for example 4 in number, are distributed on the external face of the plate 9a around a circle centered on the axis A. Each coil 8a is supported by one of its lateral flanges on the external face of the plate 9a. The outer face of this support flange has a central pin 16 which is housed in a corresponding recess 17 of the plate 9a to center the coil 8a. Each coil 8a is fixed to the plate 9a by a fixing means such as a screw (not shown) which freely crosses an opening 18 of the coil to be screwed into a complementary tapped opening 19 of the plate 9a.

The ejection system 10a is designed to eject all the trap wires from the coils 8a simultaneously and in different directions, and for this purpose it comprises a central part linked to the cutting function of an opening in a wall of the body of the mine, and a peripheral part linked to the ejection function of the trap wires through this opening.

The central part of the ejection system 10a is carried by a support 20, generally circular, which is housed partly in the central recess 12 of the plate 9a and fixed to the latter by any suitable means (not shown).

The support 20 has on its face opposite the plate 9a a circular central recess 21 aligned on the axis A and whose diameter is substantially equal to the internal diameter of the sleeve 13. On its other face, the support 20 has a central opening 22 of smaller diameter which opens at the center of the recess 21.

A housing 23 is thus delimited by the sleeve 13 of the plate 9a and the recess 21 of the support 20, to receive the central part of the ejection system 10a which comprises a movable element 25 of telescopic type formed of a piston 26 and of a sleeve 27 attached concentrically around the piston 26.

More specifically, the piston 26 consists of a hollow tubular element closed at one end by a bottom wall 28, and which delimits an internal chamber 30 with a diameter substantially equal to that of the central opening 22 of the support 20. The piston 26 is positioned so as to come to bear freely by its open end on the bottom wall of the recess 21 of the support 20 while being aligned on the axis A. Towards its open end, the piston 26 has an annular boss outer forming heel drive 26a. The sleeve 27 also freely bears at one end on the bottom wall of the recess 21 of the support 20. It has towards this end an external annular boss forming a stop 31 and towards its other end an internal annular boss forming a stop 32, with a flange 33 provided on its external peripheral surface and which bears on the stop 14 of the sleeve 13 of the plate 9a.

The piston 26 and the sleeve 27 extend substantially over the same height, and when they are supported on the support 20, only a central boss 35 provided outside of the bottom wall 28 of the piston 26 protrudes at the beyond the sleeve 13.

The face 3 of the body 2 of the mine 1 adjacent to the coil 8a-ejection system 10a assembly is formed by a circular flange 40 fixed at its periphery to the body 2 of the mine 1. A circular plate 41 of smaller diameter is joined by one face against the flange 40 and is connected to the piston 26 of the moving element 25. More specifically, the central boss 35 of the piston 26 engages by force in a corresponding recess 36 provided in the center of the plate 41. The plate 41 forms a shearing means for cutting a cover 42 in the central part of the flange 40 according to a diameter corresponding to that of the plate 41.

A pyrotechnic charge 45 with its initiation device is housed inside the opening of the support 20 and is mounted so that the gases resulting from its initiation penetrate into the internal chamber 30 of the moving element 25 so as to to train it on the move.

The central part of the ejection device 10a therefore comprises the shearing plate 41 and its control device constituted by the movable element 25 driven in translation by the load 45 to cut the cover 42, and it is completed by a peripheral part described below to ensure the ejection of the trap wires 6 through the opening 43 delimited by the cover 42.

A weight forming a projectile 50 is attached to the free end of each trap wire 6 and is housed in an ejection chamber 51. Advantageously, each ejection chamber 51 is provided in the body of the coil 8a associated in the form of 'A passage oriented along an oblique axis A1 passing right through the body of the coil. The axis A1 substantially forms an axis of 45 ° with the axis A.

Overall, each ejection chamber 51 is closed at one end by the shear plate 41, and it communicates at the other end by a connecting duct 54 with the housing 23 delimited in the central part of the ejection system 10a.

Each connecting duct 54 is constituted by a radial channel 55 formed in the support 20. The channel 55 opens at one end into the ejection chamber 51, while its other end is obstructed by the sleeve 27 of the moving element 25 which forms a time delay device for delaying the arrival of the gases in the ejection chambers 51 of the projectiles 50.

Of course, mine 1 comprises a set of means specific to its function as a mine and which become operational when the mine detonates, that is to say when one of the trap wires detects the presence of a foreign body. These means have been grouped together under the reference M and will not be described below, the invention essentially relating to the system for ejecting the trap wires.

We will now describe the operating principle of this first embodiment of the system for ejecting the trap wires 6 from the mine 1 with particular reference to FIGS. 1 to 5.

The mines 1 are either ejected from a container, or dropped from a vector such as a shell often called a "cargo shell" because it can contain several mines. The shell is either fired by an artillery piece on the ground, or dropped from an airplane. As soon as the shell flies over the mining area, the mines are ejected from the shell. In all cases, the mines fall in free fall towards the ground, being generally braked by suitable means known per se. Once the mines are immobilized on the ground by being supported by one of their flat faces, the ejection system of the trap wires of each mine is controlled by the internal electronics of the mine so as to make it operational.

According to the invention, only one of the ejection systems 10a or 10b must be controlled, for example the ejection system 10a if the mine rests on the ground by its flat face 4. For this, a detection device ( not shown) of the support face of the mine 1 on the ground, comprising for example a mercury relay, makes it possible to inhibit the ejection system 10b associated with the support face 4.

Load 45 is initiated by the internal electronics of the mine. The gases resulting from this initiation enter the internal chamber 30 of the piston 26 of the moving element 25.

In a first phase (Figure 2), the gas pressure exerted on the bottom wall 28 of the piston 26 causes a sudden displacement of the piston 26 which slides inside the sleeve 27, the latter remaining fixed by means of its collar 33 bearing on the stop 14 of the sleeve 13 of the plate 9a. In its movement, the piston 26 drives the shearing plate 41 which causes the cutting of the cover 42 in the flange 40 on a diameter corresponding to the outside diameter of the plate 41. This first phase ends when the piston 26 comes to bear by its heel drive 26a on the stop 32 of the socket 27. The moving element 25 is then momentarily immobilized while the gas pressure increases inside the volume delimited by the chamber 30 of the piston 26 and the socket 27.

In a second phase (FIG. 3), the pressure of the gases inside the abovementioned volume is such that it causes shearing of the collar 33 of the sleeve 27 which then becomes free in translation inside the sleeve 13 of the plate 9a. The piston 26 is again driven in displacement, and its heel 26a in abutment on the stop 32 of the bush 27 causes the simultaneous drive of the latter until the abutment 31 of the bush 27 comes to bear on the stop 14 of the sleeve 13 of the plate 9a, which has the effect of stopping the moving element 25. However, the energy accumulated by the moving element 25 during its movement is sufficient to cause the plate to be ejected by inertia shear 41 and cover 42.

During its movement (Figure 4), the sleeve 27 has gradually released the radial channels 55 of the support 20 to allow the passage of gases to the ejection chambers 51 of the projectiles 50. This results in the simultaneous ejection of these projectiles 50 through the opening 43 with concomitant unwinding of the trap wires 6 wound on the coils 8a.

Mine 1 is then operational, and as soon as one of the trap wires detects the presence of a body foreign, the mine's explosion mechanism is validated in a manner known per se. Advantageously, the pyrotechnic charge 45 associated with the coils 8b adjacent to the face 4 of the mine 1 which rests on the ground can be initiated just before the explosion of the mine so that it is lifted from the ground. As for the ejection system 10a, the gases cause the displacement of the moving element 25, the cutting of the flange 40 and, by reaction, the lifting of the mine which leaps before explosion in order to improve its efficiency.

In a second embodiment of the invention shown in Figure 6, there is essentially provided a variant at the timing device which delays the ejection of projectiles, the means for cutting and ejecting the cover 42 being similar to those described in the first embodiment.

The connection conduit 54 which provides the connection between the ejection chambers 51 and the housing 23 of the movable assembly 25 is here constituted by two annular chambers 60 and 61 centered on the axis A, but offset one with respect to the other along this axis. The chamber 61 which communicates with the ejection chambers 51 is wider than the chamber 60. The two chambers 60 and 61 communicate with each other by an annular passage 62.

The sleeve 27 of the movable assembly 25 initially closes the passage between the housing 23 and the first chamber 60 of the connecting duct 54. After cutting the cover 42, the displacement of the sleeve 27 driven by the piston 26 makes it possible to open the connecting duct 54. The gases present in the housing 23 pass into the first chamber 60 where they relax, then into the second chamber 61 which causes a pressure drop. Thus, the combined action of these two chambers 60 and 61 makes it possible to delay the ejection of the projectiles 50.

In this second embodiment, it is provided a variant at the shear plate 41, as shown in Figure 7. The shear plate 41 has a central pin 65 located on the axis A and which is housed partly inside a recess 66 provided in the adjacent end surface of the piston 26. This guide pin 65 makes it possible to improve the cutting of the cover 42 which is carried out at the same time over the entire circumference, then the ejection of the cover 42 and of the tray. shear 41 along axis A, that is to say along the axis of piston 26.

Finally, according to a third embodiment shown in FIG. 8, variants are provided at the level of the moving element 25 and at the level of the means for ejecting the projectiles 50.

In this embodiment, the moving element 25 is limited to the piston 26 which is in direct sliding contact with the internal wall of the sleeve 13 of the plate 9a which supports the coils 8a, the sleeve 13 no longer having the stopper 14 to immobilize the moving element 25 after its displacement. The connecting duct 54 is formed of at least one channel 70 located in the plate 9a and which opens at one end into the housing 23 and at the other end to the internal face of the plate 9a or opposite face to that which supports the coils 8a, of a chamber 71 delimited by a flange 72, provided with a peripheral rim 73, attached to the internal face of the plate 9a, and of channels 74 which all open into chamber 71. These channels 74 are located in the plate 9a and communicate with the ejection chambers 51, respectively.

A delay or slow combustion pyrotechnic charge 75 and a conventional additional charge 76 are housed in the channel 70 adjacent to the housing 23, and they constitute a timing device.

According to this third embodiment, the charge 45 possibly supplemented by a charge additional 45a is initiated to move the piston 26. As for the other embodiments, the displacement of the piston 26 causes the cutting of a cover 42 by the shear plate 41, but in this case the piston 26 is ejected simultaneously with the cover 42 and the shear plate 41.

In parallel, the combustion of the charges 45 and 45a causes the initiation of the slow combustion charge 75 which, after a certain delay, causes the initiation of the charge 76 whose gases are used to eject the projectiles 50.

Such a delay device 75 and 76 could possibly be envisaged in the case of the two other embodiments described above.

Of course, the invention is in no way limited to the preceding embodiments given solely by way of examples, but it includes all of the technical equivalents of the means described without departing from the scope of the invention as defined by the claims. following. In particular, modifications can be made at the level of the shearing plate 41 to facilitate cutting of the cover 42.

Claims (20)

1. A trip wire mine of the type comprising a hollow body in which several trip wires are housed each wound around a coil, and an automatic ejection system for the wires which comprises a device to release an opening in one wall of the mine body, a projectile attached to a free end of each trip wire and means to eject the projectiles through the opening in the body of the mine with the accompanying unwinding of the wires wound around the coils, characterised in that the device to free the ejection opening (43) of the projectiles (50) comprises a shearing means (41) housed in the body (2) of the mine to cut out in a wall (40) of the latter a part forming a lid (43) and an ejection device for this lid (42).
2. A trip wire mine of the type comprising a hollow body having two parallel plane faces (3,4) acting as bearing surfaces on the ground, characterised in that the shearing means (41) is formed by a plate bearing on the other plane face (3) and integral with a mobile element (25) commanded in displacement along an axis A perpendicular to the plate and which passes by the centre of the latter.
3. A trip wire mine according to Claim 2, characterised in that the mobile element (25) also forms the ejections device for the lid (42).
4. A trip wire mine according to Claims 2 or 3, characterised in that each plane face (3,4) of the body (2) of the mine is formed by a flange (40), and in that the shearing plate (41) is of a circular shape and has smaller dimensions than the flange (40), the plate (41) being centred on axis A.
5. A trip wire mine according to any one of Claims 2 to 4, characterised in that the coils (8a) are supported in a horizontal position on one face of a plate (9a) and are distributed in a circle centred on axis A, and in that the ejection system (10a) is carried by a support (20) fastened on the other face of the plate (9a), this support (20) and the plate (9a) marking out a housing (23) centred on axis A and in which is mounted the element (25) being mobile in translation and comprising at least a piston (26) fastened to the shearing plate (41).
6. A trip wire mine according to Claim 5, characterised in that the piston (26) of the mobile element (25) is commanded in translation along axis A by the gas pressure resulting from the ignition of a pyrotechnic charge (45), which penetrates into the housing (23) of the mobile element (25).
7. A trip wire mine according to Claim 6, characterised in that each projectile (50) is mounted in an ejection chamber (51) oriented along an axis Al which makes an angle of roughly 45° with axis A.
8. A trip wire mine according to Claim 7, characterised in that the ejection chamber (51) of each projectile (50) is formed in the body (2) of the coil (8a) of the associated trip wire (6).
9. A trip wire mine according to Claim 7 or 8, characterised in that the means to eject the projectiles (50) are formed of the gas pressure resulting from the initiation of the aforementioned pyrotechnic charge (45), and in that each ejection chamber (51) of the projectiles (50) communicates with the housing (23) of the mobile element (25) by means of a connecting channel (54).
10. A trip wire mine according to Claim 9, characterised in that the ejection system (10a) also comprises a retarder device to delay the arrival of the gases in the ejection chambers (51) of the projectiles (50).
11. A trip wire mine according to Claim 10, characterised in that the mobile element (25) also comprises a case (27), forming the retarder device, brought around the piston (26) to close the connecting channel (54), and in that the case (27) is connected in a telescopic manner to the piston (26) to be integral in translation with the latter after cutting out of the lid (42) so as to open the connecting channel (54).
12. A trip wire mine according to Claim 11, characterised in that the plate (9a) of the ejection system (10a) comprises a limit stop (14) to restrict the movement of the mobile element (25), and in that the shearing plate (41) is forced onto the piston (26), and in that the lid (42) and the plate (41) are ejected by inertia.
13. A trip wire mine according to Claim 11, characterised in that the mobile element (25), the shearing plate (41) and the lid (42) are ejected from the body (2) of the mine by means of the gas pressure resulting from the initiation of the pyrotechnic charge (45).
14. A trip wire mine according to Claim 10, characterised in that the connecting channel (54) is formed of at least two ring-shaped chambers (60,61) forming the retarder device.
15. A trip wire mine according to Claim 8, characterised in that the means to eject the projectiles (50) are formed of the gas pressure resulting from the initiation of at least one additional pyrotechnic charge (76), and in that each projectile (50) ejection chamber (51) communicates with the housing (23) of the mobile element (25) by means of a connecting channel (54), the additional charge (76) being placed in the channel (54).
16. A trip wire mine according to Claim 15, characterised in that the ejection system (10a) also comprises a retarder device to delay initiation of the additional charge (76).
17. A trip wire mine according to Claim 16, characterised in that the retarder device is composed of a slow combustion charge (75) placed in the connecting channel (74), this charge (75) being initiated by the combustion of the charge (45) used to displace the mobile element (25) and which initiates the additional charge (76).
18. A trip wire mine according to any one of Claims 15 to 17, characterised in that the mobile element (25) composed of the piston (26) is ejected with the lid (42).
19. A trip wire mine according to any one of Claims 2 to 18, characterised in that it comprises two similar ejection systems (10a, 10b) working in conjunction with two sets of coils (8a, 8b) placed in the vicinity of the two parallel plane faces (3,4) of the body (2) of the mine, respectively.
20. A trip wire mine according to Claim 19, characterised in that the ejection system (10a or l0b) adjacent to the face of the mine bearing on the ground is activated before the explosion of the mine to cause the latter to lift up.

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