Title of Invention

LASER-INITIATED SIMULTANEOUS IGNITION SYSTEM

Abstract

The present invention relates to a laser-initiated simultaneous ignition system for large-calibred an1lnunition, which system comprises, in the cartridge chamber of the ammunition, several propellant modules one behind another and having explosive, wherein each propellant module has a detonation channel and the detonation channel of all the propellant modules form a single, straight-line and continuous duct for the laser beam, and wherein arranged in each propellant module there is an output apparatus for at least one portion of the laser beam, which output apparatus, when a laser beam impinges thereon, causes the propellant module associated with the output apparatus to be ignited.

Full Text

The invention relates to a laser-initiated simultaneous ignition system having at least one ignition charge and one propellant module which has an explosive material. Various methods for initiation, that is to say ignition, of ignition charges and explosive materials by laser light are known from the prior art. In this case, the laser beam can be focused via an optical conductor directly or via downstream focusing optics onto the ignition charge, or can be aimed directly at the explosive material or the ignition charge. In boundary conditions which are matched to laser initiation, the ignition process can be initiated with a relatively small amount of laser energy. In the case of an ignition system for a plurality of propellant modules or ignition charges, at least one optical conductor is in each case routed to each propellant module or each ignition charge, each optical conductor at the same time being fed with appropriate laser light, and the ignition charges or propellant modules being ignited by it simultaneously. In unfavourable mechanical and spatial conditions, for example in the cartridge chamber of an armoured howitzer, this ignition system is unsuitable, because of its space requirement and its sensitivity, as well as for cost reasons. The object of the invention is to provide a simplified and improved laser-initiated simultaneous ignition system. In the case of the ignition system according to the invention, an output apparatus is arranged along the beam path of a laser beam, in order to output at least a part of the laser beam or light. The output apparatus ignites the ignition charge or the explosive material of the propellant module when the laser beam strikes it. The output apparatus outputs sufficient light energy in the laser beam to ignite the explosive material or the ignition charge. Each ignition charge and each propellant module along the optical axis of the laser beam is ignited virtually simultaneously. Since no optical conductors are used to carry the laser light, this results in a very simple, compact and reliable simultaneous ignition system. The position of the propellant modules and ignition charges, that is to say their distance from and position with respect to the laser light source, can vary without this resulting in the ignition reliability deteriorating. Each propellant module and each ignition charge preferably has a detonation channel in which the output apparatus is arranged. The propellant modules and ignition charges can be arranged in such a manner that the detonation channels form a single, straight and continuous channel for the laser beam. In the case of this arrangement, a plurality of ignition charges and propellant modules can be arranged in a line and can be detonated virtually simultaneously, for example in the cartridge chamber of an armoured howitzer. In a preferred embodiment, a part of the laser beam or light is output from each output apparatus simultaneously, that is to say, ignoring the propagation speed of the light, the laser light strikes all the output apparatuses simultaneously, which results in the propellant modules and ignition charges also being ignited simultaneously. The output apparatus may in this case be an optical element, which diverts a part of the laser beam or light onto the explosive material or the ignition charge. In this case, this may be an optically partially permeable element, which reflects only a part of the incident laser beam, and allows the remaining part to pass through, with the beam cross-section unchanged, to the next propellant module or detonation charge; alternatively, it may be a mirror which diverts only a part, for example a sector of the laser beam, onto the explosive material or the ignition charge. In another embodiment, the output apparatus may alternatively be provided as a pyrotechnic element which is struck by at least a part of the laser beam, as a result of which it is detonated and, for its part, detonates the explosive material of the respective propellant module or the ignition charge. The use of pyrotechnic elements allows a very cost-effective solution to be achieved. The pyrotechnic output apparatus can also be provided in such a manner that it masks out in each case only a part of the laser beam, so that the remaining part of the laser beam can pass through the respective detonation channel, can strike the output apparatuses of the following propellant modules and ignition charges, and can ignite them. In a first embodiment, the pyrotechnic output apparatus is provided with an annular shape, the output apparatus no longer masking out the laser beam in the region of at least a part of the internal circumference of the ring only once this region has detonated and burnt away, so that the laser beam then strikes the output ring of the following propellant module or the following ignition charge. In this case, it is particularly advantageous if the inner part of the ring has a short axial length, that is to say has less substance and, in consequence, can be detonated and burns away faster. This results in the inner part burning away very quickly, so that even after a short time, the laser beam can ignite the inner circumferential ring of the output ring of the following propellant module or of the following ignition charge. In another embodiment, the pyrotechnic output apparatus has a part which projects into the detonation channel centre, so that this part of all the output apparatuses can be covered by the laser beam simultaneously. To this end, these parts must be arranged offset with respect to one another in such a manner that they do not completely shadow another projecting part of another propellant module. In consequence, virtually simultaneous ignition of all the propellant modules and ignition charges can be achieved using a cost-effective, pyrotechnic ignition technique which is simple to manufacture. In a preferred embodiment, the pyrotechnic output apparatus is a film which is coated with explosive material, for example a plastic film. The explosive material of the film and of the propellant module is preferably selected or modified in such a manner that it has a high absorption level in the region of the wavelength of the laser light. In con- sequence, the minimum amount of laser energy for igniting the explosive material of the propellant module or of the film is reduced, so that ignition can be accomplished with a lower energy density and with a miniaturized laser system. Accordingly the present invention provides a laser-initiated simultaneous ignition system for large-calibred ammunition, which system comprises, in the cartridge chamber of the ammunition, several propellant modules one behind another and having explosive, wherein each propellant module has a detonation channel and the detonation channel of all the propellant modules form a single, straight-line and continuous duct for the laser beam, and wherein arranged in each propellant module there is an output apparatus for at least one portion of the laser beam, which output apparatus, when a laser beam impinges thereon, causes the propellant module associated with the output apparatus to be ignited. A plurality of exemplary embodiments of the invention will be explained in more detail in the following text with reference to the drawings, in which: Fig. la shows a laser-initiated ignition system having five ignition charges arranged in a distributed manner, Fig. lb shows a second embodiment of a laser-initiated ignition system having six propellant modules, each of which has an optical beam splitter as the output apparatus, Fig. 2 shows a plan view of an annular pyrotechnic output apparatus, Fig. 3 shows a longitudinal section through the output apparatus in Fig. 2, Fig. 4 shows a cross-section of the pyrotechnic output apparatus in Fig. 2 with the internal circumferential edge ignited and partially burnt away, Fig. 5 shows a longitudinal section through the pyrotechnic output apparatus in Fig. 2 with the internal circumferential edge partially burnt away, Fig. 6 shows a further embodiment of a pyrotechnic output apparatus with a triangular, annular cross-section, Fig. 7 shows a cross-section through a further embodiment of a pyrotechnic output apparatus having a wedge-shaped annular cross-section, Fig. 8 shows a further embodiment of a pyrotechnic output apparatus having a part which projects towards the centre like a sector of a circle, Fig. 9 shows a further embodiment of a pyrotechnic output apparatus having a web which projects radially inwards, Fig. 10 shows a further embodiment of a pyrotechnic output apparatus having a web which forms the circle diameter, Fig. 11 shows a further output apparatus of a pyrotechnic output apparatus having a web which is continuous but does not run through the centre of the circle, Fig. 12 shows a further pyrotechnic output apparatus having a segment which projects into the detonation channel, and Fig. 13 shows a cross-sect ion of one embodiment of the ignition system having pyrotechnic output apparatuses as in Fig. 12. ment of a laser-initiated ignition system having five ignition charges 27. A laser 22' emits a laser beam 23' which is diverted a plurality of times via four partially permeable mirrors 18', and finally strikes the ignition charge 27 arranged in the last position. Those beam elements 25' which are in each case not reflected by the mirrors 18' but pass through them likewise strike those ignition charges 27 which are in each case located behind the mirror 18' , in each case viewed from the direction of the incoming laser beam 23'. The partially permeable mirrors 18' thus form output apparatuses through which in each case a part of the light of the laser beam 23' is output in order to ignite the respective ignition charge 27, the energy density of the output beam element 25' being sufficient to ignite the respective ignition charge 27. Figure lb illustrates the cartridge chamber 10 of a gun whose open end 11 is connected to a gun barrel, which is not shown, with a projectile. The cartridge chamber 10, which is formed by a tube 12, contains six annular propellant modules 15, which have explosive material and are located one behind the other. In its centre, each propellant module 15 has a continuous detonation channel 14. Each propellant module 15 consists of an explosive material ring 16, whose internal circumference is lined with an ignition sleeve 17, which surrounds the detonation channel 14. A small glass plate 18, which is positioned approximately at 45° to the longitudinal axis of the detonation channels 14, is arranged in the ignition sleeve 17 as the optical output apparatus. The small glass plate 18 forms a partially permeable mirror for laser light which is fed into the detonation channels 14. Instead of the glass plate 18, the optical beam splitter used may also be a transparent film, a prism or a partially permeable mirror. The detonation modules 15 are arranged one behind the other in such a manner that their detonation channels 14 form a single, straight and continuous channel for a laser beam. A laser 22 is arranged in a plug 21 at the closed end of the cartridge chamber 10, in such a manner that its optical axis is in a line with the longitudinal axes of the propellant modules 15. The laser beam 23 emerging from the laser 22 thus runs along the optical longitudinal axis of the detonation channels 14. The small glass plates 18 act as optical beam splitters, which each output a part of the laser beam light. Together with the special propellant modules 15, the laser 22 forms a laser-initiated simultaneous ignition system. The laser light can also be fed into the detonation channels 14 through an optical conductor, rather than by the laser 22. The parallel laser beam is broadened and has a diameter of a few millimetres. In other embodiments, the laser beam can also be focused or divergent. In order to ignite the propellant modules 15, the laser 22 emits a short high-energy laser pulse which passes through the detonation channels 14 of the propellant modules 15. Approximately 15% of the light in the laser beam is in each case reflected radially outwards through the small glass plates 18 into the detonation channels 14, where the reflected beam 25 ignites the ignition sleeve 17. The ignition sleeve 17, for its part, ignites the explosive material ring 16. The laser beam 23 strikes all the small glass plates 18 of the propellant modules 15 simultaneously, for which reason the propellant charges 15 are also all ignited simultaneously. Figures 2 to 13 show exemplary embodiments in which the initiation, that is to say the ignition, of the propellant charges is carried out by a pyrotechnic element rather than by an optical element. Figures 2 to 12 show only pyrotechnic output apparatuses, without any explosive material ring surrounding them. The pyrotechnic output apparatuses are in each case inserted into the explosive material ring 16, instead of the optical output apparatuses of the propellant module in Fig. lb. Figures 2 to 5 illustrate the simplest embodiment of a pyrotechnic output apparatus 30. This output apparatus 30 consists of a cylindrical ignition ring 31, in whose centre a free, continuous channel 32 is arranged. When the laser beam 23 strikes it, the ignition ring 31 is ignited at the end of its internal circumferential edge facing the laser light and burns away from the inside to the outside. In the process, the internal diameter of the channel 32 is enlarged, in such a manner that the laser beam 23 strikes an ignition ring 31' located behind it, and likewise ignites it. This process takes place so quickly that these pyrotechnic output apparatuses 30, 30' are ignited virtually simultaneously, so that the explosive material rings are also ignited virtually simultaneously. Figures 6 and 7 illustrate further rotationally symmetrical pyrotechnic output apparatuses 3 01# 3 02, which each consist of an ignition ring 35, 40. While the embodiment of the ignition ring in Fig. 6 has the annular cross-section of an equilateral triangle with a tip pointing inwards, the ignition ring 3 8 in Fig. 7 has a wedge-shaped cross-sectional profile. A common feature of both ignition rings 35, 38 is that the axial thickness of the internal circumferential edge of the ignition ring 35, 3 8 is very small internally and increases only towards the outside. This ensures that the inner part of the ignition ring burns away quickly and, in consequence, that the subsequent ignition ring or rings is or are also ignited quickly. In every case, the laser beam must have a larger diameter than the internal region of the pyrotechnic ignition apparatuses where there is no material. Figures 8 to 11 illustrate pyrotechnic ignition rings which are not rotationally symmetrical but are asymmetric and in which a part like a segment projects into the detonation channel and into the laser beam cross-section. A common feature of all these output apparatuses is that a plurality of such output elements can be arranged one behind the other without shadowing one another. This ensures that, provided the ignition rings are arranged correctly, the laser beam simultaneously strikes a plurality of ignition rings arranged one behind the other, which, in turn, ensures simul-taneous ignition of the output apparatuses, and thus of the explosive material of the propellant modules. In the case of the output apparatus 3 9x in Fig. 8, a part 41 proj ects, like a sector of a circle, integrally from the outer ring 40 towards the centre. In the case of the embodiment of the output apparatus 3 92 illustrated in Fig. 9, a web-like part 42 projects radially inwards from the outer ring 40. In the case of the exemplary embodiment in Fig. 10, a web 43 which passes through the centre point and forms the diameter splits the detonation channel 14 of the pyrotechnic output apparatus 393 into two halves. A further pyrotechnic ignition apparatus 3 94 is illustrated in Fig. 11. A web 44 which passes through the detonation channel 14 connects two points on the outer ring 4 0, in such a manner that it splits the detonation channel 14 asymmetrically into two parts. Fig. 12 illustrates a further embodiment of a pyrotechnic output apparatus 3 95, in which the outer ring 4 0 is supplemented by a part 43 which is like a segment and projects inwards. The pyrotechnic ignition apparatuses illustrated in Figs. 2 to 12 are implemented in the form of a tablet, but can also be designed as a film. In particular, the pyrotechnic output apparatuses 391-395 in Figs. 8 to 12 can also be designed as a thin film, coated with magnesium. Furthermore, the film can be coated with a dye or explosive material containing graphite, as a result of which the absorption level for the incident laser light can be increased. Thin films on a plastic base can also be used, with a conventional ignition mixture made of lead styphnate, AZM, black powder, etc., possibly also with a burning accelerator or a primary ignition material. It is also possible to use explosive materials matched to the laser wavelength and having a high laser light absorption level and a low initiation energy. By the selection of suitable beam guidance optics or by deflection of the light beam, it is also possible to reduce the size of the beam diameter and to increase the energy density, which is important for reliable initiation, for example by means of an annular beam structure instead of a beam structure in the form of a disc. In this case, the explosive material which the laser light strikes should be selected so as to ensure that it burns away quickly and that, while burning away, it is removed well. Since the propellant modules may be in any axial position, for example in the cartridge chamber of an armoured howitzer along a one-metre-long longitudinal axis, and the number of propellant modules may also vary, the propellant modules which can be initiated by a laser beam pulse provide a variable ignition system which is ideal for such applications. There is no need to use a focused beam for ignition, but only a broadened, parallel laser beam with an approximately constant energy density. This broadened beam allows any propellant module to be ignited, irrespective of its axial position. Fig. 13 illustrates a cross-section of a cartridge chamber 12 with six propellant modules, each having one pyrotechnic ignition apparatus 3 95. The parts 43 (which project inwards and are like segments of circles) of the pyrotechnic output apparatuses 3 95 are each arranged twisted through 60° with respect to one another, so that each segment 43 of the output apparatuses 395 fills part of the overall cross-section of the detonation channel 14. A laser beam whose diameter is approximately the same as that of the detonation channel 14 thus covers all six segments 43 of the output apparatuses 3 95. This results in all the propellant modules 15 being ignited simultaneously. An optical output apparatus can likewise be designed in the form of the pyrotechnic output apparatuses 39-395 in Figs. 8 to 12, the part projecting into the detonation channel being designed as a mirror which is at approximately 45° to the detonation channel longitudinal axis and deflects a part of the laser beam outwards. The laser-initiated simultaneous ignition system also allows explosive material samples or ignition elements to be ignited. WE CLAIM: 1. A laser-initiated simultaneous ignition system for large-calibred ammunition, which system comprises, in the cartridge chamber (10) of the ammunition, several propellant modules (15) one behind another and having explosive (16), wherein each propellant module (15) has a detonation channel (14) and the detonation channel (14) of all the propellant modules (15) form a single, straight-line and continuous duct for the laser beam (23), and wherein arranged in each propellant module (15) there is an output apparatus (18, 30, 30l5 302, 391 - 395) for at least one portion (25) of the laser beam (23), which output apparatus, when a laser beam (23) impinges thereon, causes the propellant module (15) associated with the output apparatus (18, 30, 30j, 302, 39j -395) to be ignited. 2. The laser-initiated simultaneous ignition system according to claim 1, wherein a portion of the laser beam (23) is simultaneously de-coupled by each output apparatus (18,18\39,-395). 3. The laser-initiated simultaneous ignition system according to claim 1 or 2, wherein the output apparatus (18) is an optical element which deflects a portion (25) of the laser beam (23) onto the explosive (16). 4. The laser-initiated simultaneous ignition system according to claim 1 or 2, wherein the output apparatus is a pyrotechnic element (30i, 302, 391 - 395) upon which at least one portion of the laser beam (23) impinges, whereby it is ignited and for its part ignites the explosive (16) of the respective propellant module (15). 5. The laser-initiated simultaneous ignition system according to claim 4, wherein the pyrotechnic output apparatus (39! -395) is a film that is coated with explosive. 6. The laser-initiated simultaneous ignition system according to any one of claims 1 to 5, wherein the detonating channel (14) is circular, 7. The laser-initiated simultaneous ignition system according to any one of claims 4 to 6, wherein the explosive of the foil and of the propellant module is coloured in such a way that it has a high absorption coefficient in the range of the wave-length of the laser light. 8. A laser-initiated simultaneous ignition system substantially as herein described with reference to the accompanying drawings.

Documents:

2006-mas-1997- abstract.pdf

2006-mas-1997- claims duplicate.pdf

2006-mas-1997- claims original.pdf

2006-mas-1997- correspondence others.pdf

2006-mas-1997- correspondence po.pdf

2006-mas-1997- description complete duplicate.pdf

2006-mas-1997- description complete original.pdf

2006-mas-1997- drawings.pdf

2006-mas-1997- form 1.pdf

2006-mas-1997- form 26.pdf

2006-mas-1997- form 4.pdf

2006-mas-1997- pct.pdf