Ammunition and explosives – Shells – With safety means
Patent
1996-11-29
1998-11-24
Johnson, Stephen M.
Ammunition and explosives
Shells
With safety means
102431, 102466, 102464, F42B 528, F42B 530
Patent
active
058410635
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method and arrangement intended to impart to fixed service ammunition for barrel weapons, for example charged with so-called LOVA powder, such properties that allow to limit to the greatest possible extent the damage to the environment in the event of a hit on or other damage to an ammunition store containing such ammunition which produces a subsequent ammunition fire or other increase in pressure in the ammunition. The arrangement included in the invention is constituted by a cartridge case designed to accomplish the above.
BACKGROUND OF THE INVENTION
LOVA powder is the general designation for a relatively new type of powder including fine-particle crystalline explosive substances. LOVA powders are best thought of as insensitive replacements for the conventional nitrocellulose powders. In the development of LOVA powders, efforts have therefore been made to produce powders which under non-pressurized conditions have burning properties which are as calm as possible but during combustion at high pressure have at least equally good propellent properties as the nitrocellulose powders which they are intended to replace. The designation LOVA stands for "low vulnerability ammunition" and in Swedish specialist texts the designation "lagkanslig ammunition" {insensitive ammunition} is sometimes seen for this type of product.
The great pressure-sensitivity of LOVA powders as far as their own burning speed is concerned means that there would be much to gain if it were possible to rapidly reduce the pressure in a LOVA powder which has accidentally been ignited, for example by a shell hit on such an ammunition store. By means of such a pressure reduction, it would thus be possible to radically to change the course of events from a runaway combustion, which within a very short period of time would lead to the ammunition store explosion, to a relatively calm combustion.
In particular as far as fixed ammunition is concerned, where the powder is enclosed in sealed cases made of metal, plastic or in certain instances combustible material, it is, however, a matter of considerable difficulty, in the event of an ammunition fire, to bring about a sufficiently rapid pressure reduction within each charge to prevent these individually and the ammunition store as a whole from exploding. It is also relevant that the problem with an ammunition fire can be assumed to apply to vehicles, example, tanks, armoured vehicles, ships, and the like where space is always very restricted. It must moreover be possible for the pressure reduction to take place automatically without any personnel being involved. Moreover, and perhaps most important of all, any measure taken must not in the least endanger the function of the ammunition in its regular use.
SUMMARY OF THE INVENTION
According to the present invention, the abovementioned problems have now been solved by providing the cartridge cases with longitudinal, accurately adapted weakenings. The weakenings are designed in such a manner that they do not jeopardize the functioning of the ammunition on firing with the weapon in question by the case then being supported from the outside by the cartridge chamber of the weapon, but which, in the event of an ammunition fire when the ammunition is outside the cartridge chamber of the weapon, as a result of the pressure increase within the respective case when the powder inside the same is ignited, result in at least one well-defined longitudinal splitting open per case with an open area of such a size that the powder is combusted more calmly and is thus prevented from exploding. In particular as far as ammunition charged with LOVA powder is concerned, which thus in itself burns quite calmly when it is not pressurized; the gains in the form of reduced damage to the environment thus become considerable. The weakening according to the invention is not merely to be designed in such a manner that the split which is opened is sufficiently large to prevent further pressure increases in the powder, b
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English Translation of Roy (54858).
English Translation of Weib et al. (306 475).
English Translation of Bavnier (557 101).
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Hellkvist Dan
Loinder Erik
Bofors AB
Johnson Stephen M.
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