EP0098640A1 - Projectile fuze firing means - Google Patents

Projectile fuze firing means Download PDF

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Publication number
EP0098640A1
EP0098640A1 EP83200939A EP83200939A EP0098640A1 EP 0098640 A1 EP0098640 A1 EP 0098640A1 EP 83200939 A EP83200939 A EP 83200939A EP 83200939 A EP83200939 A EP 83200939A EP 0098640 A1 EP0098640 A1 EP 0098640A1
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EP
European Patent Office
Prior art keywords
striker
primer
crystal
housing
electrodes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83200939A
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German (de)
French (fr)
Inventor
Roger Beuchat
Edmond Butschi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mefina SA
Original Assignee
Mefina SA
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Filing date
Publication date
Application filed by Mefina SA filed Critical Mefina SA
Publication of EP0098640A1 publication Critical patent/EP0098640A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
    • F42C11/00—Electric fuzes
    • F42C11/02—Electric fuzes with piezo-crystal

Definitions

  • Devices for firing a projectile primer comprising a striker acting on a piezoelectric element placed between two electrodes and intended to supply the electrical energy necessary for firing the primer, comprising a step-down transformer to connect the electrodes of the piezoelectric element to the primer.
  • the invention aims to improve the energy efficiency of the firing device.
  • the invention also aims to combine the security offered by low impedance primers and the simplicity advantages of a firing device constituted by a piezoelectric element.
  • the device according to the invention is characterized in that the piezoelectric element is constituted by a disc-shaped crystal placed in a housing of circular cylindrical shape, a movable part having a circular cylindrical portion being slidably mounted in said housing, this movable part being subjected to the action of a spring to exert an initial pressure on the crystal, this part being arranged on the path of the striker, but distant from the latter, so as to transmit to the piezoelectric element the shock produced by the striker coming to abut against this mobile part.
  • the firing device is mounted in a projectile rocket comprising an annular part 1.
  • This device comprises a low impedance primer 2 mounted in a primer holder 3.
  • the primer holder 3 is retained by a timer mechanism 4 provided with a finger 5 in the position illustrated in the drawing, in which there is an interruption of the pyrotechnic chain, since the primer 2 is placed at a place where it cannot communicate fire to a detonator 6 , from which it is separated by a partition 7.
  • the above arrangement is well known in the art and is therefore not described in more detail.
  • the front part of the rocket is provided with an annular part 8 having a rim 9 for retaining a striker 10 constituted by a cap made of synthetic resin, in which is embedded a part 11 made of metal, such as steel or hard brass.
  • the striker 10 is kept pressed against the internal surface of the rim 9 by a spring 12 bearing against a sleeve 13 of insulating resin.
  • This sleeve 13 constitutes a housing for a movable metal part 14 slidingly mounted inside this sleeve and subjected to the action of a spring 15 bearing against its front face and against the striker.
  • the part 14 is called a hammer and is separated from the striker by a distance of a few millimeters.
  • the part 14 is pressed elastically against a piezoelectric element 16 constituted by a disk-shaped crystal.
  • This crystal is disposed at the bottom of a housing of circular cylindrical shape delimited by the sleeve 13 and the front face of the annular part 1 forming an anvil.
  • the crystal 16 is therefore clamped between two metal parts which are intended to exert on it the forces necessary for obtaining the ignition voltage and which at the same time constitute the electrodes for taking this voltage.
  • the voltage supplied by the crystal 16 upon impact is brought to a transformer 17 retained in a sleeve 18 in the annular part 1, the input conductors of the transformer being constituted, on the one hand, by the part 1, and , on the other hand, by a metal rod 19 in contact with the hammer 14 via an elastic blade 20.
  • the transformer 17 is a step-down transformer and, thanks to the fact that it must transmit pulses of very short duration, it can be constituted simply by two coaxial windings without iron carcass. In principle, these two windings are carried on a coil, the central part of which constitutes a non-ferrous core for the said coils.
  • the secondary winding of the transformer 17 is connected by conductors not shown to electrical contacts to bring the ignition voltage to the primer 2 at low impedance when the latter has arrived in its firing position, after the expiration of the expected time for safety of mouth. These electrical contacts can for example be combined with the locking finger 5.
  • the arrangement described is very advantageous, since the crystal is held firmly on its two faces and on its periphery, so that it can withstand very high pressures without its functioning being compromised. Excellent results are obtained by providing a slight bending and a slight convexity of the faces of the parts 1 and 14 which bear against the faces of the crystal, the latter being flat. The measurements demonstrated that when the striker struck the hammer 14, this the latter has a resonance phenomenon, so that the crystal produces at least two successive voltage spikes.
  • the striker acquires a high speed at the time of impact, it strikes vigorously the part 14 and a very brief, but very high pressure is obtained, which is favorable from the point of view of the electrical voltage.
  • the masses displaceable during impact are limited to the mass of the striker, the latter being mainly constituted by the mass of the metal part 11 and like
  • the resin cap of the striker is relatively large, the firing device has a high sensitivity and can operate during impacts on very soft ground, for example on loose snow.

Abstract

The firing means comprises a striker (10, 11) striking a hammer (14) for compressing a piezoelectric crystal (16) which is connected to the input of a transformer (17). The latter reduces the voltage so that it is possible to engage a low-impedance fuse (2). In the armed position, the fuse (2) comes into the axis of the projectile opposite the detonator (6). <IMAGE>

Description

On connaît déjà des dispositifs de mise à feu d'une amorce de projectile, comprenant un percuteur agissant sur un élément piezo-électrique placé entre deux électrodes et destiné à fournir l'énergie électrique nécessaire à la mise à feu de l'amorce, comprenant un transformateur abaisseur de tension pour relier les électrodes de l'élément piezo-électrique à l'amorce.Devices for firing a projectile primer are already known, comprising a striker acting on a piezoelectric element placed between two electrodes and intended to supply the electrical energy necessary for firing the primer, comprising a step-down transformer to connect the electrodes of the piezoelectric element to the primer.

L'invention a pour but d'améliorer le rendement énergétique du dispositif de mise à feu.The invention aims to improve the energy efficiency of the firing device.

L'invention a également pour but de combiner la sécurité offerte par les amorces à basse impédance et les avantages de simplicité d'un dispositif de mise à feu constitué par un élément piezo-électrique. A cet effet, le dispositif selon l'invention est caractérisé en ce que l'élément piezo-électrique est constitué par un cristal en forme de disque placé dans un logement de forme cylindrique circulaire, une partie mobile présentant une portion cylindrique circulaire étant montée coulissante dans ledit logement, cette partie mobile étant soumise à l'action d'un ressort pour exercer une pression initiale sur le cristal, cette partie étant disposée sur le chemin du percuteur, mais distante de celui-ci, de façon à transmettre à l'élément piezo-électrique le choc produit par le percuteur en venant buter contre cette partie mobile.The invention also aims to combine the security offered by low impedance primers and the simplicity advantages of a firing device constituted by a piezoelectric element. To this end, the device according to the invention is characterized in that the piezoelectric element is constituted by a disc-shaped crystal placed in a housing of circular cylindrical shape, a movable part having a circular cylindrical portion being slidably mounted in said housing, this movable part being subjected to the action of a spring to exert an initial pressure on the crystal, this part being arranged on the path of the striker, but distant from the latter, so as to transmit to the piezoelectric element the shock produced by the striker coming to abut against this mobile part.

La figure unique du dessin annexé représente, schématiquement et à titre d'exemple, une forme d'exécution du dispositif de mise à feu selon l'invention.The single figure of the accompanying drawing shows, schematically and by way of example, an embodiment of the firing device according to the invention.

Le dispositif de mise à feu est monté dans une fusée de projectile comprenant une pièce annulaire 1. Ce dispositif comprend une amorce 2 à basse impédance montée dans un porte-amorce 3. Avant le départ du coup, le porte-amorce 3 est retenu par un mécanisme temporisateur 4 muni d'un doigt 5 dans la position illustrée au dessin, dans laquelle il y a interruption de la chaîne pyrotechnique,car l'amorce 2 est disposée à un endroit où elle ne peut pas communiquer le feu à un détonateur 6,dont il est séparé par une cloison 7. La disposition ci-dessus est bien connue dans la technique et n'est donc pas décrite plus détaillée.The firing device is mounted in a projectile rocket comprising an annular part 1. This device comprises a low impedance primer 2 mounted in a primer holder 3. Before the start of the shot, the primer holder 3 is retained by a timer mechanism 4 provided with a finger 5 in the position illustrated in the drawing, in which there is an interruption of the pyrotechnic chain, since the primer 2 is placed at a place where it cannot communicate fire to a detonator 6 , from which it is separated by a partition 7. The above arrangement is well known in the art and is therefore not described in more detail.

La partie avant de la fusée est munie d'une pièce annulaire 8 présentant un rebord 9 pour retenir un percuteur 10 constitué par une calotte en résine synthétique,dans laquelle est noyée une pièce 11 en métal, tel.que de l'acier ou du laiton dur. Le percuteur 10 est maintenu appuyé contre la surface interne du rebord 9 par un ressort 12 prenant appui contre un manchon 13 en résine isolante. Ce manchon 13 constitue un logement pour une partie mobile 14 métallique montée coulissante à l'intérieur de ce manchon et soumise à l'action d'un ressort 15 prenant appui contre sa face avant et contre le percuteur. La pièce 14 est dénommée marteau et est séparée du percuteur par une distance de quelques millimètres.The front part of the rocket is provided with an annular part 8 having a rim 9 for retaining a striker 10 constituted by a cap made of synthetic resin, in which is embedded a part 11 made of metal, such as steel or hard brass. The striker 10 is kept pressed against the internal surface of the rim 9 by a spring 12 bearing against a sleeve 13 of insulating resin. This sleeve 13 constitutes a housing for a movable metal part 14 slidingly mounted inside this sleeve and subjected to the action of a spring 15 bearing against its front face and against the striker. The part 14 is called a hammer and is separated from the striker by a distance of a few millimeters.

Ainsi la pièce 14 est pressée élastiquement contre un élément piezo-électrique 16 constitué par un cristal en forme de disque. Ce cristal est disposé au fond d'un logement de forme cylindrique circulaire délimité par le manchon 13 et la face avant de la pièce annulaire 1 formant enclume. Le cristal 16 est donc serré entre deux pièces métalliques qui sont destinées à exercer sur lui les forces nécessaires pour l'obtention de la tension d'allumage et qui constituent en même temps les électrodes pour prélever cette tension.Thus, the part 14 is pressed elastically against a piezoelectric element 16 constituted by a disk-shaped crystal. This crystal is disposed at the bottom of a housing of circular cylindrical shape delimited by the sleeve 13 and the front face of the annular part 1 forming an anvil. The crystal 16 is therefore clamped between two metal parts which are intended to exert on it the forces necessary for obtaining the ignition voltage and which at the same time constitute the electrodes for taking this voltage.

La tension fournie par le cristal 16 lors de l'impact est amenée à un transformateur 17 retenu dans un manchon 18 dans la pièce annulaire l,les conducteurs d'entrée du transformateur étant constitués, d'une part, par la pièce 1, et, d'autre part, par une tige métallique 19 en contact avec le marteau 14 par l'intermédiaire d'une lame élastique 20.The voltage supplied by the crystal 16 upon impact is brought to a transformer 17 retained in a sleeve 18 in the annular part 1, the input conductors of the transformer being constituted, on the one hand, by the part 1, and , on the other hand, by a metal rod 19 in contact with the hammer 14 via an elastic blade 20.

Le transformateur 17 est un transformateur abaisseur de tension et, grâce au fait qu'il doit transmettre des impulsions de durée très brève, il peut être constitué simplement par deux enroulements coaxiaux sans carcasse de fer. En principe, ces deux enroulements sont portés sur une bobine dont la partie centrale constitue un noyau non ferreux pour les dites bobines. L'enroulement secondaire du transformateur 17 est relié par des conducteurs non représentés à des contacts électriques pour amener la tension d'allumage à l'amorce 2 à basse impédance lorsque cette dernière est arrivée dans sa position de mise à feu, après écoulement de la durée prévue pour la sécurité de bouche. Ces contacts électriques peuvent par exemple être combinés avec le doigt de verrouillage 5.The transformer 17 is a step-down transformer and, thanks to the fact that it must transmit pulses of very short duration, it can be constituted simply by two coaxial windings without iron carcass. In principle, these two windings are carried on a coil, the central part of which constitutes a non-ferrous core for the said coils. The secondary winding of the transformer 17 is connected by conductors not shown to electrical contacts to bring the ignition voltage to the primer 2 at low impedance when the latter has arrived in its firing position, after the expiration of the expected time for safety of mouth. These electrical contacts can for example be combined with the locking finger 5.

Lorsque le projectile atteint un but, le percuteur est déplacé brusquement vers l'arrière et la pièce 11 vient heurter le marteau 14, ce dernier transmettant au cristal 16 l'onde de choc produite par le percuteur 10. Il en résulte une pression élevée et de courte durée sur le cristal avec production consécutive d'énergie électrique dans des conditions d'impédance élevée.When the projectile reaches a goal, the striker is suddenly moved backwards and the part 11 strikes the hammer 14, the latter transmitting to the crystal 16 the shock wave produced by the striker 10. This results in high pressure and of short duration on the crystal with consecutive production of electrical energy under conditions of high impedance.

La disposition décrite est très avantageuse, car le cristal est maintenu fermement sur ses deux faces et sur son pourtour, de sorte qu'il peut résister à des pressions très élevées sans que son fonctionnement soit compromis. On obtient des résultats excellents en prévoyant un léger bombage et une légère convexité des faces des pièces 1 et 14 qui prennent appui contre les faces du cristal, ces dernières étant planes. Les mesures ont démontré que lors du choc du percuteur contre le marteau 14, ce dernier présente un phénomène de résonnance, de sorte que le cristal produit au moins deux pointes de tension successives.The arrangement described is very advantageous, since the crystal is held firmly on its two faces and on its periphery, so that it can withstand very high pressures without its functioning being compromised. Excellent results are obtained by providing a slight bending and a slight convexity of the faces of the parts 1 and 14 which bear against the faces of the crystal, the latter being flat. The measurements demonstrated that when the striker struck the hammer 14, this the latter has a resonance phenomenon, so that the crystal produces at least two successive voltage spikes.

Grâce au fait que le percuteur acquiert une vitesse élevée au moment de l'impact, il vient frapper vigoureusement la pièce 14 et l'on obtient une pression très brève,mais très élevée,ce qui est favorable au point de vue de la tension électrique fournie. Comme, d'une part, les masses déplaçables lors de l'impact sont limitées à la masse du percuteur, celle-ci étant principalement constituée par la masse de la pièce métallique 11 et comme, d'autre part, la calotte en résine du percuteur est relativement grande, le dispositif de mise à feu présente une grande sensibilité et peut fonctionner lors des impacts sur sol très tendre, par exemple sur de la neige non tassée.Thanks to the fact that the striker acquires a high speed at the time of impact, it strikes vigorously the part 14 and a very brief, but very high pressure is obtained, which is favorable from the point of view of the electrical voltage. provided. As, on the one hand, the masses displaceable during impact are limited to the mass of the striker, the latter being mainly constituted by the mass of the metal part 11 and like, on the other hand, the resin cap of the striker is relatively large, the firing device has a high sensitivity and can operate during impacts on very soft ground, for example on loose snow.

Claims (4)

1. Dispositif de mise à feu d'une amorce (2) de projectile, comprenant un percuteur (10) agissant sur un élément piezo-électrique (16) placé entre deux électrodes (1, 14) et destiné à fournir l'énergie électrique nécessaire à la mise à feu de l'amorce (2),comprenant un transformateur (17) abaisseur de tension pour relier les électrodes de l'élément piezo-électrique à l'amorce (2),caractérisé en ce que l'élément piezo-électrique (16) est constitué par un cristal en forme de disque placé dans un logement de forme cylindrique circulaire, une partie mobile (14) présentant une portion cylindrique circulaire étant montée coulissante dans ledit logement, cette partie mobile étant soumise à l'action d'un ressort (15) pour exercer une pression initiale sur le cristal (16),cette partie (14) étant disposée sur le chemin du percuteur (10),mais distante de celui-ci, de façon à transmettre à l'élément piezo-électrique (16) le choc produit par le percuteur en venant buter contre cette partie mobile. (14)1. Device for igniting a projectile primer (2), comprising a striker (10) acting on a piezoelectric element (16) placed between two electrodes (1, 14) and intended to supply electrical energy necessary for igniting the primer (2), comprising a step-down transformer (17) for connecting the electrodes of the piezoelectric element to the primer (2), characterized in that the piezo element -electric (16) is constituted by a disc-shaped crystal placed in a housing of circular cylindrical shape, a mobile part (14) having a circular cylindrical portion being slidably mounted in said housing, this mobile part being subjected to the action a spring (15) for exerting an initial pressure on the crystal (16), this part (14) being disposed on the path of the striker (10), but distant from the latter, so as to transmit to the element piezoelectric (16) the shock produced by the striker coming to abut against this movable part. (14) 2. Dispositif selon la revendication 1, caractérisé en ce que les électrodes sont constitués par le fond du logement et par la face de la pièce mobile (14) qui est tournée vers le cristal (16),ce fond et cette face étant l'un convexe et l'autre concave.2. Device according to claim 1, characterized in that the electrodes are constituted by the bottom of the housing and by the face of the movable part (14) which faces the crystal (16), this bottom and this face being the one convex and the other concave. 3. Dispositif selon la revendication 1, caractérisé en ce que le transformateur (17) est constitué par deux enroulements électriques coaxiaux, ces enroulements étant montés sur un noyau non ferreux.3. Device according to claim 1, characterized in that the transformer (17) consists of two coaxial electrical windings, these windings being mounted on a non-ferrous core. 4. Dispositif selon la revendication l,caractérisé en ce que le percuteur présente une partie avant (10) en résine synthétique, cette partie étant déplaçable en direction de l'élément piezo-électrique (16),une pièce métallique (11) de plus petite dimension que la pièce en résine étant solidaire de cette dernière et agencée pour venir frapper ladite partie mobile (14)-4. Device according to claim l, characterized in that the striker has a front part (10) of synthetic resin, this part being movable towards the piezoelectric element (16), a metal part (11) more small dimension that the resin part being integral with the latter and arranged to strike said movable part (14) -
EP83200939A 1982-06-29 1983-06-23 Projectile fuze firing means Withdrawn EP0098640A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH3974/82 1982-06-29
CH397482A CH648110A5 (en) 1982-06-29 1982-06-29 DEVICE FOR FIRING A PROJECTILE PRIMER.

Publications (1)

Publication Number Publication Date
EP0098640A1 true EP0098640A1 (en) 1984-01-18

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EP83200939A Withdrawn EP0098640A1 (en) 1982-06-29 1983-06-23 Projectile fuze firing means

Country Status (5)

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EP (1) EP0098640A1 (en)
CH (1) CH648110A5 (en)
DK (1) DK297283A (en)
ES (1) ES8503125A1 (en)
FI (1) FI832364A0 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0121494A1 (en) * 1983-03-07 1984-10-10 Mefina S.A. Armour-piercing projectile fuze

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2987998A (en) * 1948-06-08 1961-06-13 Seth W Booth Fuze for a bomb
US3624451A (en) * 1970-05-04 1971-11-30 Avco Corp Efficient low voltage piezoelectric power supply
CH543065A (en) * 1971-09-06 1973-10-15 Sarmac Sa Device for electrically igniting the explosive charge of a projectile

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2987998A (en) * 1948-06-08 1961-06-13 Seth W Booth Fuze for a bomb
US3624451A (en) * 1970-05-04 1971-11-30 Avco Corp Efficient low voltage piezoelectric power supply
CH543065A (en) * 1971-09-06 1973-10-15 Sarmac Sa Device for electrically igniting the explosive charge of a projectile

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0121494A1 (en) * 1983-03-07 1984-10-10 Mefina S.A. Armour-piercing projectile fuze

Also Published As

Publication number Publication date
ES523646A0 (en) 1984-06-01
ES8503125A1 (en) 1984-06-01
DK297283D0 (en) 1983-06-28
FI832364A0 (en) 1983-06-28
DK297283A (en) 1983-12-30
CH648110A5 (en) 1985-02-28

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