FR2807510A1 - Detonator for pyrotechnic device such as a grenade has catch holding primary module separate from main charge equipped with two or more locks - Google Patents

Abstract

The detonator has a housing (104) with a control lever and percussion mechanism (128) interacting with a primary pyrotechnic module (105) to set off a main charge (119). The primary module is held separate from the main charge by a catch which is held in the safety position by two or more mechanical locks (101, 126) requiring a double manipulation to release them. One of the locks (101) is formed by a lever and pin (125).

Description

The present invention relates to the field of igniter plugs for pyrotechnic devices.

The present invention finds particular but not exclusively application in grenades usable by hand or with mechanical means of launching whatever their functions, for example explosives, smoke, lighting or combined.

Numerous documents relating to igniter plugs have been published.

We can for example refer to documents FR-A-2338478, FR-A-2354506, FR-A-2428233.

It has moreover been described in document FR-A-2686688 a delay igniter plug for pyrotechnic device, in accordance with attached FIG. 1 comprising a body 4 provided with a control mechanism comprising a trigger lever 1 a percussion mechanism 28 cooperating with a primary pyrotechnic module 5, 3, 9, 13 capable of initiating the charge 19 of the associated device and axially displaceable in the body towards the main charge, means 2 for holding the primary pyrotechnic module 5 axially separated from the main charge 19 and a screen, 15 interposed between the main charge and the primary pyrotechnic module.

More specifically according to document FR-A-2686688, the means 2 for holding the primary pyrotechnic module 5 axially spaced from the main charge 19 are exclusively mechanical means, actuated by the trigger lever 1.

More precisely still, according to the document FR-A-2686688, the means for holding the pyrotechnic module 5 spaced axially from the main charge 19, comprise jumper 2 housed in the body 4 of the plug and engaged with the primary pyrotechnic module 5, the trigger lever 1 comprising a member 1 a for extracting the jumper, when the trigger lever 1 is released relative to the body of said plug.

The operation of the known device illustrated in Figure 1 is essentially as follows. To initiate the system, the grenade is pinned by extracting, by combined rotation and traction, a pin 25. Then the grenade is launched. The trigger lever 1 is no longer held in its locking position, the elastic stress of a spring 22, by means of a striker 24, makes the lever 1 pivot. After a rotation of about 30 the finger 1 a of the trigger lever 1 comes to bear on the jumper 2 and begins its extraction. In the following phase the rotation of the lever, the striker 24 escapes and strikes the initiation of the jumper 2 having not yet released the primary delay pyrotechnic module 5. By inertia, the trigger lever 1 ends its rotation and releases from the body 4 by driving the jumper 2, which has the effect of unlocking the primary delay pyrotechnic module 5. As this always subject to the thrust of the striker 24 in association with the spring 22, the primary pyrotechnic delay module 5 is translated which clears the screen 12a, the solid element 12a of a cup 12 coming from the bottom of a cell 29 of a cup 18. A micro-detonator 13 is then in the position of initiation of detonation by radial effect.

The present invention now aims to improve the device described in document FR-A-2686688.

This object is achieved in the context of the present invention by means of an igniter plug for pyrotechnic device, in particular grenade with manual or mechanical launching, comprising a body provided with a control mechanism comprising a trigger lever and a percussion mechanism cooperating with module primary pyrotechnic capable of ensuring the initiation of the charge of the associated device and axially movable in the body towards the main charge and mechanical means for holding the primary pyrotechnic module axially separated from the main charge in an initial safety position, characterized in that the means for holding the primary pyrotechnic module axially spaced from the main charge comprise a latch resiliently biased from an initial safety position in which the latch interferes with the movement path of the primary pyrotechnic module to prevent its movement towards the main charge , worm s a release position in which the lock deviates the movement path of the primary pyrotechnic module, the lock itself being initially maintained in the initial safety position by at least two mechanical blocking means, so that the release of the lock requires double manipulation of these blocking means.

Those skilled in the art will understand that the structure thus proposed makes it possible to guarantee perfect reliability of the device by preventing any unauthorized inadvertent use.

According to another advantageous characteristic of the present invention, one of the means for blocking the lock is formed by the trigger lever.

According to another characteristic of the invention, one of the means for blocking the lock is formed by a pin.

According to another advantageous characteristic of the invention, the means for holding the primary pyrotechnic module axially spaced apart from the main charge further comprises a jumper housed in the body of the plug and initially engaged with the primary pyrotechnic module, the jumper being provided with 'A means capable of cooperating with the trigger lever to cause the extraction of the jumper when the release lever is released relative to the body of said plug.

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description to follow and with reference to the appended drawings, given by way of limiting examples and in which - FIG. 1 previously described represents a known igniter plug according to the state of the art as illustrated in document FR-A-2686688, - Figure 2 schematically shows the igniter plug structure according to the present invention, in the initial safety position, - Figures 3 to 7 show the same device at different successive stages of its operation, - Figures 8 and 9 show the device dies in two cases of non-operation resulting from the safety means incorporated in the device, following implementation in accordance with the required protocol, - Figure 10 schematically represents a pin according to an alternative embodiment of the present invention on, - Figure 11 schematically shows means of cooperation defined between the latch and the trigger lever according to an alternative embodiment of the invention, - Figure 12 schematically shows a device according to an optional alternative embodiment of the present invention.

The igniter plug illustrated in the appended figures applies in particular to hand grenades. It is not however limited to this particular application.

Found in the appended figures, a support body 104. This can be made of plastic material loaded with glass fibers, light alloy or any other equivalent material.

The body 104 carries a primary pyrotechnic module 105 and a secondary pyrotechnic module 1 The secondary module 117 is preferably fixed on the body 104, while the primary pyrotechnic module 105 is capable of displacement in translation along an axis OO between an initial position of safety (illustrated in Figure 1) and a subsequent working position (illustrated in Figure 7), as will be explained later.

The device illustrated in Figures 2 and following further comprises, in a manner known per se, a trigger lever 101 provided with a transverse locking pin 125 equipped with a gripping ring.

The igniter plug illustrated in FIGS. 2 and following also includes a striker device 128 rotatably mounted on the body 104 around an axis 121 transverse to the axis of relative translation OO defined between the primary pyrotechnic module 105 and the secondary pyrotechnic module 117. The striker 128 is biased towards a percussion position of the primary pyrotechnic module 105 by a spring 122 wound for example around the transverse axis 121. However, initially, the striker 128 is kept away from the primary pyrotechnic module 105 by the lever trigger 101.

As described in document FR-A-2686688, preferably, the primary pyrotechnic module 104 is initially kept away from the secondary pyrotechnic module 117 by a jumper The jumper 102 comprises a main branch which extends transversely to the axis OO and which thus interferes, in the initial storage position, both with the body 104 and the primary pyrotechnic module 105.

The lever 101 is engaged by a front spout 101c with a step of the body 104. Preferably, the body 104 further comprises two curved lateral ramps (not illustrated in the appended figures to simplify the illustration) arranged under the lever 101 so to guide the latter in rotation after removal of the pin 125.

The primary pyrotechnic module 105 is preferably a delay module. It comprises a metal case 110, for example of light alloy, at the base of which is crimped a cup 112 whose length and diameter correspond to those of an axial chamber 129 formed in the secondary pyrotechnic module 117. The module 105 carries the minus a delay 109.

The metal case 110 contains at its upper end a percussive primer 103, held for example by crimping and protected by a varnish or a resin. The position of the percussive primer 1 on the metal case 105 and the amplitude of the striker 128 are determined so that when the release lever 101 is withdrawn, the striker strikes the primer 103 under the effect of the spring stress Between the percussive primer 3 and the cup 12, the metal case 110 successively houses, along the axis OO, from the percussive primer 103 a retarding composition 109, an initiation composition 111 and a microphone - Detonator 113 which constitutes the primary explosive of the pyrotechnic chain. The base of the bucket 112 is integral with a metal pad 11 The case 110 of the primary pyrotechnic module 105 is partially inserted in a case 116 of the secondary pyrotechnic module 117. However, an axial spacing allows the case 110 to slide at the inside the case 116 along the axis OO, when the case 110 is released.

Preferably, sealing means are interposed between the case 110 of the primary pyrotechnic module 105 and the case 116 of the secondary pyrotechnic module 117. According to the particular nonlimiting embodiment illustrated in the appended figures, these sealing means are formed of a flexible sheath referenced 116a, fixed by its ends respectively to the case 110 in the vicinity of the percussive primer 103 and to the case 116.

The secondary pyrotechnic module 117 preferably comprises a detonation relay constituted by an aluminum cup containing a secondary explosive 119 and a closure capsule or ring 15 which, in combination with the tablet 112a disposed at the base of the cup 112 of the primary module 105 forms a screen between the micro-detonator 113 and the secondary explosive 119 which constitutes the main priming charge. To this end, as can be seen in the appended FIG. 2, in the initial safety position, during storage, the tablet 112a is located at the level of the closure capsule 115, in a bore formed therein.

We will now describe the particular means proposed in the context of the present invention for improving the safety of the igniter plug which has just been described.

As mentioned above, essentially, according to the invention, the means for holding the primary pyrotechnic module 105 in a position axially spaced from the main charge 119 comprise a latch 150.

The latch 150 is resiliently biased from an initial safety position illustrated in FIG. 2 to a release position shown in FIG. 5.

In the initial safety position, the latch 150 interferes with the path of movement of the primary pyrotechnic module 105 to prevent its movement towards the main charge 119. On the contrary, in the release position the latch 150 deviates from the path of movement of the primary pyrotechnic module 105.

Furthermore, in the context of the invention, the latch 150 is itself initially maintained in the initial safety position as illustrated in FIG. 2 by at least two mechanical locking means.

Thus, the release of the lock 150 requires a double manipulation of these blocking means.

More precisely still, as can be seen in the appended figures, within the framework of the invention, preferably the two mechanical locking means of the lock 150 are formed one by the release lever 101, the other by the pin 125 .

More precisely still, according to the particular embodiment shown in the appended figures, the latch 150 has the general shape of an L comprising two main branches 152 and 154 generally oriented orthogonally to one another.

latch 150 is mounted for rotation between the initial safety position and the release position around an axis 160 located in the vicinity of the intersection between the two branches 152 and 154.

The axis of rotation of the lever 150 can be embodied by a pin engaged both with the body 104 and the lever 150, or any equivalent means.

The elastic member urging the latch 150 towards the release position from the initial safety position, is preferably formed of a pin spring 170 having a spiral wound around the axis 160 and two end branches bearing respectively one on the body 1 the other on the latch 150.

In the initial safety position, one of the branches 152 of the latch 150 extends substantially parallel to the axis OO of translation of the primary pyrotechnic module 105. The branch 152 extends in the direction of the end of the primary pyrotechnic module 105 adjacent to the primer 103, from the axis of rotation 160. And as can be seen in the appended FIG. 2, the free end of this branch 152 serves as a stop, in the initial safety position, for a step 106 formed on the case 110 of the primary pyrotechnic module 105.

Thus, in the initial safety position, the latch 150 prohibits movement of the case 110 towards the main load 119.

The second branch 154 of the latch 150, in the initial position, extends substantially transversely to the axis O-O of translation of the case 110, away from this axis O-O from the axis of rotation 160.

Furthermore, as can be seen in the appended figures, preferably at its free end, the second branch 154 of the latch 150 is provided with a return or spout 155 passing through a passage 101a made in the trigger lever 101 so that the spout 155 comes into engagement with the external surface of the trigger lever 101 in the initial safety position.

The orientation of the contact surfaces thus defined between the spout 155 the trigger lever 101, as well as the surface condition of the contact zones, are defined so that the torque resulting from the friction force exerted on the spout 155 of the latch 150 by the trigger lever 101 is greater than the engine torque applied to the latch 150 by the spring 170. Thus, the cooperation defined between the trigger lever 101 and the latch 150 prevents movement of the latch 150 towards the release position, under the effect of the spring 170, as long as the trigger lever 101 has not been manipulated in approaching the axis OO of the machine, to release the spout 155 and the latch 150, as will be explained by the after.

It will also be noted that, as illustrated in the appended figures, in the initial safety position, one of the branches 126 of the pin 125, which branch 126 is transverse to the axis OO, serves as a support for the branch 152 of the lock 150. More precisely still, the branch 126 of the pin 125 serves as a support for the radially external surface of the branch 152.

The operation of the device according to the present invention illustrated in Figures 2 and following annexed is essentially as follows. In the initial safety position, the striker 128 is immobilized by the trigger lever 101. The latter is itself immobilized by the pin 125. The latch 150 is immobilized in the safety position, on the one hand by the trigger lever thanks to the spout 155 and, on the other hand, by the safety pin thanks to the branch 126. The case 110 of the primary pyrotechnic module 105 is held in a position remote from the secondary pyrotechnic module 117, on the one hand by the latch 150 and, on the other hand by the jumper 102.

To use the igniter plug in accordance with the present invention illustrated in FIGS. 2 and following, it is first of all advisable to press the trigger lever 101 against the body of the machine as shown diagrammatically in FIG. 3 under arrow referenced F and as appears from a comparative examination of Figures 2 and 3.

As illustrated in FIG. 3, this manipulation of the trigger lever 101 generates a clearance between the spout 155 of the latch 150 and the trigger lever 101.

In a second step, it is necessary to extract the safety pin 125 as shown diagrammatically in FIG. 4, for example by using the conventional "turn - pull" functions specific to such a pin.

As can be seen in FIG. 4, the latch 150 having been previously released from its cooperation with the trigger lever 101, the extraction of the branch 126 from the pin 125 completely releases the latch 150 and authorizes the rotation thereof around its axis 160 under the effect of the stress of the spring 170.

The primary pyrotechnic module 105 is then released from the latch 150 as seen in FIG. 4.

In the case of a craft launched by hand, the craft can then be launched in a conventional manner per se.

The striker 128, under the effect of the armed spring 122 rotates the released lever 101. The striker 128 leaves the contact of the lever 101 and strikes the primer 103 can ensure firing of the delay 109 after a free stroke, for example of the order greater than the angle necessary to initiate the primer (as illustrated in Figure 5). As illustrated in FIG. 6, the trigger lever 101 then finishes its rotation and drives the jumper or locking pin 102. Typically the extraction of the jumper or locking pin 102 is carried out in approximately 51100's after percussion of the primer 103. This arrangement makes it possible to ensure security, capable of protecting the user of the machine in the event of instantaneous operation of the primary module.

The case 110 of the primary pyrotechnic module 105 is thus freed translation along the axis O-O due to the ejection of the jumper 102.

The residual force of the striker 128 on the case 110 allows it to translate to the secondary pyrotechnic module 117 and to align the pyrotechnic chain by positioning the micro-detonator 113 at the heart of the detonation relay of the secondary pyrotechnic module 117.

When the delay 109 arrives at the end of combustion, it excites the primary micro-detonator 113 which in turn initiates the detonation relay 119.

At the time of this implementation, the device is in the position illustrated in FIG. 7.

However, it will be noted that, as illustrated in FIG. 8, in the event of incorrect manipulation of the machine, for example by removing the pin 125 without taking hold of the trigger lever 101, the latch 150 remains blocked by the trigger lever 101, so that the latch 150 prevents movement of the primary pyrotechnic module 110.

Similarly, in the event that the trigger lever 101 is taken in hand without ejecting the pin 125, the device is in the position illustrated in FIG. 3, and the pin holding the latch 150 in the initial safety position, the module primary pyrotechnic 110 remains in the initial locked position.

Furthermore, if for some reason, the primary pyrotechnic module 110 were to be excited in the storage position, as illustrated in FIG. 9, the initiation of the micro-detonator 113 would result in crimping the solid part of the micro-holder. detonator formed by cup 112, in the ring 115 of the detonation relay. Typically, a disc of the order of 4 mm thick is then obtained which isolates the primary part or micro-detonator 113 from the secondary part or detonation relay, thereby prohibiting its initiation. The full disc therefore constitutes a physical rupture of the pyrotechnic chain, leading to storage security.

Of course the present invention is not limited to the particular embodiments which have just been described, but extends to all variants in accordance with its spirit.

In particular, as will now be described with reference to FIGS. 10 to 12, the device according to the present invention can be equipped with additional means capable of preventing its operation in the event of the pin 125 being ejected without taking hold of the lever. trigger 101.

According to a first variant illustrated in FIG. 10, the additional safety means provided for this purpose include means suitable for preventing the ejection of the pin 125 if the trigger lever 101 is not taken in hand. More precisely still, according to the variant illustrated in FIG. 10, these means consist of a shoulder 27 formed on the branch 126 of the pin 125, in order to allow the eccentricity rest between the pin 125 and the trigger lever 101.

Thus, if the user tries to remove the pin 125 before having manipulated the trigger lever 101, the shoulder 127 abuts against the lever 101 and the removal of the pin 125 is prohibited.

On the contrary, if the trigger lever 101 is previously pressed against the body of the machine as illustrated in FIG. 3, the pin is then aligned with the bore of the trigger lever 101 so that the withdrawal of the pin 125 is authorized.

Two other additional means are intended in particular to prevent inadvertent operation of the machine in the event of an accidental fall after removal of the pin 125 and without taking hold of the lever.

One of these means, according to the variant illustrated in FIG. 11, provides means with complementary shapes between the spout 155 of the latch 150 and the trigger lever 101. More precisely still, as illustrated in FIG. 11, the spout 155 has a tenon 156 or equivalent directed generally radially inwards in the direction of the axis OO, and capable of penetrating into a complementary bore 101b formed on the trigger lever 101.

Thus, according to the variant illustrated in FIG. 11, even when the pin 125 is withdrawn, the lock 150 cannot reach the release position until the trigger lever is pressed against the body of the machine to allow the post 156 to escape the bore 101 b.

According to yet another alternative embodiment illustrated in FIG. 12, a material, such as a viscoelastic rubber, can be interposed between the trigger lever 101 of the igniter plug and the body of the machine.

 This material is generally referenced 190 in the attached FIG. 12. It is preferably an eraser whose hardness increases with the speed of stress. This makes it possible to avoid the displacement of the trigger lever 101 during very sharp stress resulting from a fall, but on the other hand allows the displacement of the trigger lever 101 during a grip of conventional lever 101.

Claims (4)

<B><U>REVENDICATIONS</U> </B> 1. Igniter plug for pyrotechnic device, in particular grenade with manual or mechanical launching, comprising a body (104) provided with control mechanism comprising a lever (101) for triggering percussion mechanism (128) cooperating with a primary pyrotechnic module (105) suitable to initiate the charge (119) of the associated device and axially displaceable in the body (104) towards the main charge (119) and mechanical means (102) for holding the primary pyrotechnic module (105) axially separated of the main charge (1 in an initial safety position, characterized in that the means (102) for holding the primary pyrotechnic module (105) axially separated from the main charge (119) comprise a latch (1 resiliently biased, d an initial safety position in which latch (150) interferes with the path of movement of the primary pyrotechnic module (105) to prevent its movement towards the main charge (119), towards a release position in which the latch (150) deviates from the path of movement of the primary pyrotechnic module (1 the latch (150) being itself initially maintained in the initial safety position by at least two mechanical locking means (101, 126) so that the release of the lock (150) requires a double manipulation of these locking means. 2. Igniter plug according to claim 1, characterized in that one of the locking means of the latch (150) is formed by the trigger lever (101). 3. Igniter plug according to one of claims 1 or 2, characterized in that one of the means for blocking the trigger lever (101) is formed by a pin (125). 4. Igniter plug according to one of claims 1 to characterized in that the primary pyrotechnic module (105) is further immobilized in the initial safety position, distant from the secondary pyrotechnic module (117), by a jumper (102) which interferes with the body (1 and is adapted to be removed when the trigger lever (101) is ejected. Ignitor plug according to one of claims 1 to 4, characterized in that the latch (150) has the general shape of an L comprising two branches (152, 154), which cooperate respectively with the primary pyrotechnic module (105) to act as a stop thereon and with the trigger lever (101). 1 to 5, characterized in that the latch (150) comprises a branch (154) passing through a passage (101a) formed in the trigger lever (101) having a spout (155) which rests against the external surface of the lever release (101) in the initial safety position. Igniter plug according to one of claims 1 to 6, characterized in that the latch (150) is biased towards the release position by a spring (170) mounted on its axis. Igniter plug according to one of claims 1 to 7, characterized in that the latch (150) comprises two branches (152, 154) generally orthogonal, one substantially parallel to the axis of translation of the primary pyrotechnic module (105 ) and serving as an initial stop for the latter and the other substantially radial with respect to the axis and cooperating with the trigger lever (101). 9. Igniter plug according to one of claims 1 to 8, characterized in that the primary pyrotechnic module carries at least one delay element (109). Igniter plug according to one of claims 1 to 9, characterized in that the primary pyrotechnic module (105) comprises a disc (12a) adapted to cooperate with a ring (115) of the secondary pyrotechnic module (117) to form a screen by mutual joining in the event of untimely excitation of the primary pyrotechnic module (113) in the storage position. 11. Igniter plug according to one of claims 1 to 10, characterized in that the latch (150) comprises at least one branch (152) which rests in the initial safety position against a branch (126) of a pin ( 125). 12. Igniter plug according to one of claims 1 to 11, characterized in that it comprises a pin (125) comprising a shoulder (127) so that the pin (125) can only be removed after taking hand of the release lever (101). 13. Igniter plug according to one of claims 1 to 12, characterized in that it comprises means with complementary shape (101b, 156) defined between the latch (150) and the trigger lever (101) suitable for prohibit movement of the latch (150) after removal of a pin (1 without manipulation of the release lever (101). Igniter plug according to claim 13, characterized in that the means with complementary shape comprise a lug (156) integral with the end of a branch (154) of the latch (150) able to penetrate into a complementary bore (101b) formed in the release lever (101) 15. Igniter plug according to one of claims 1 to 14 , characterized in that it comprises a viscoelastic material (1, the hardness of which increases with the speed of stress, interposed between the trigger lever (190) and the body of the machine.