Ammunition and explosives – Cartridges
Reexamination Certificate
1999-01-06
2001-03-20
Tudor, Harold J. (Department: 3641)
Ammunition and explosives
Cartridges
C102S443000, C102S470000
Reexamination Certificate
active
06202560
ABSTRACT:
The present invention relates in general to the propulsion of a projectile from the cartridge of an ammunition round in response to buildup of pressure within a gun chamber.
BACKGROUND OF THE INVENTION
Ammunition rounds from which projectiles are propelled by pressurized gases, are well known in the art, together with associated igniters, explosives, propellant charges and other common means as disclosed for example in U.S. Pat. Nos. 4,770,099, 4,799,428 and 5,123,356 to Brede et al., Yunan and Brooks et al., respectively. Usually in such prior art ammunition rounds the burning propellant is the sole gas generating source for build up of pressure within the gun chamber until motion resisting friction and inertia are overcome and the projectile starts moving. As the projectile moves forward, the accompanying increase in chamber volume relieves some of the rapid buildup of pressure due to gas generation. The peak value of the pressure is determined by competition between rate of gas generation and rate of volumetric expansion. Because the rate of gas generation depends on the amount of propellant, the strength of the gun limits the acceptable amount of propellant that can be safely burnt, which in turn limits the muzzle velocity of the projectile.
It is therefore an important object of the present invention to provide an ammunition round in which projectile movement begins in response to an independent source of gas pressure so as to safely accommodate a larger quantity of propellant usually resulting in increased muzzle velocity of the projectile.
SUMMARY OF THE INVENTION
Pursuant to the present invention, a relatively small explosive charge is detonated within the cartridge of an otherwise conventional ammunition round for rapid release of energy within a short time window preceding steady burning of the larger body of a primary propellant charge. Within such time window, the detonating explosive charge generates sufficient gas pressure to both initiate early movement of the projectile and ignite the primary propellant. The gases surrounding the explosive are compressed to form a hot plasma, which helps ignite propellants that do not easily start burning. Nevertheless, even after ignition within the short detonation time window, the primary propellant undergoes only partial burn. Eventually the major portion of the propellant undergoes steady burn, but during such steady burning of the propellant the gas pressure increases less rapidly than that in conventional ammunition because of the gas expansion accompanying early projectile movement.
In accordance with certain embodiments of the invention, the explosive charge assumes the configuration of a cord held centered along the axis of a larger diameter ullage tube. The explosive charge is thereby separated from the body of the primary propellant by a chamber of gas within a plastic capsule all enclosed within the cartridge casing. Plasma is formed from such gas when the explosive cord is detonated. The gas pressure generated by detonation of the explosive cord is exerted on the projectile to induce initial movement thereof from one axial end of the ullage tube abutting the projectile, opposite the other axial end of the tube at which the cord is ignited. Spaced injection ports along the ullage tube allow hot gases from the detonating cord to pass through and ignite the main propellant charge.
REFERENCES:
patent: 314127 (1885-03-01), Hope et al.
patent: 390232 (1888-10-01), Hurst
patent: 562535 (1896-06-01), Hurst
patent: 948148 (1910-02-01), Schenk
patent: 1556160 (1925-10-01), Riggs
patent: 4245557 (1981-01-01), Knappworst et al.
patent: 4770099 (1988-09-01), Brede et al.
patent: 4799428 (1989-01-01), Yunan
patent: 4803926 (1989-02-01), Barton et al.
patent: 5052302 (1991-10-01), Taddeo et al.
patent: 5123356 (1992-06-01), Brooks et al.
patent: 5173571 (1992-12-01), Montgomery
patent: 5465665 (1995-11-01), Diehl
patent: 5557059 (1996-09-01), Warren et al.
patent: 4841 (1892-04-01), None
patent: 2517046 (1983-05-01), None
Homer Mark
The United States of America as represented by the Secretary of
Tudor Harold J.
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