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 Cartridge munition, particularly one of medium caliberUSPTO Application #: 20080006170Title: Cartridge munition, particularly one of medium caliber Abstract: A cartridge munition, as disclosed in U.S. Pat. No. 7,107,909, includes a cartridge shell (3) and a projectile (2) inserted into it. A propulsion chamber (4) is provided within the cartridge shell that receives a propulsive charge (5) that may be ignited by means of a pyrotechnic igniter (13) and that develops propulsive gases that act on the base (8) of the projectile, driving it out of the cartridge shell. In order to prevent the pyrotechnic igniter from igniting spontaneously, and from igniting the propulsive charge (5) because of the ambient temperature or because of a fire, which would cause the cartridge shell and projectile to be separated and fly apart, it is proposed by the invention to provide exhaust channels (14) between the propulsion chamber and the exterior of the cartridge shell (3) that are filled with a fusible material, particularly a fusible metal (15). The fusible material has a lower melting point than the ignition point of the igniter (13) and of the propulsive charge (5). If the ambient temperature of the cartridge shell rises above the melting point of the fusible material, it melts, releasing the exhaust channels (14). (end of abstract) Agent: Milde & Hoffberg, LLP - White Plains, NY, US Inventor: Detlef Haeselich USPTO Applicaton #: 20080006170 - Class: 102470000 (USPTO) Related Patent Categories: Ammunition And Explosives, Cartridges, Case, Breech End Structure, With Primer Means The Patent Description & Claims data below is from USPTO Patent Application 20080006170. Brief Patent Description - Full Patent Description - Patent Application Claims
SCOPE OF THE INVENTION [0001] The invention relates to a cartridge munition, particularly to one of medium caliber, and here particularly to a practice round, with a cartridge shell and a projectile inserted into it, and with the cartridge shell mechanically attached to the projectile. A propulsion chamber is provided at the base of the cartridge shell to receive a propulsive charge that, for example, may be ignited using an igniter cap. After ignition, the propulsive gases from the propulsive charge act on the base of the projectile so that, after release of the mechanical bond between cartridge shell and projectile, the projectile is driven out of the cartridge shell. BACKGROUND OF THE INVENTION [0002] Such a cartridge munition is described in the U.S. Pat. No. 5,936,189. This cartridge munition is used with rapid-fire weapons of medium caliber (about 40 mm). Many such cartridges are received into a belt that is fed to the rapid-fire weapon. The propulsion chamber in the cartridge shell is sub-divided into a high-pressure chamber into which the propulsive charge is placed and a low-pressure chamber that is connected with the high-pressure chamber via exhaust apertures. Cartridge shell and projectile are mechanically connected via a central threaded connection that is formed as an intended-break point. [0003] When the propulsive charge is ignited pyrotechnically in the high-pressure chamber by means of an igniter cap, the propulsive charge burns and propulsive gases are created at high pressure that then act on the projectile base in both chambers, eventually driving the projectile out of the cartridge shell, after the intended-break point between cartridge shell and projectile is broken. [0004] A similar cartridge munition is described in the U.S. Pat. No. 4,892,038. [0005] Furthermore, practice rounds of this type are known in which only a low-pressure propulsion chamber is provided; such cartridges are known as low-velocity cartridges (Low Velocity Ammunition). [0006] Such cartridge munitions are used in large quantities, and must both be safely stored and safely transported from the manufacturer to the user. Storage and transport are generally performed using larger cases, e.g., metal cases that hold a large quantity of such cartridges. [0007] In spite of the considerable quantity of igniter material for igniter caps and propulsive charge located within a storage or transport container, storage and transport are generally simple. However, a fire in the storage or transport system during which temperatures reach and exceed 220.degree. C. presents a risk. [0008] At such temperatures, the pyrotechnic igniter charge of the igniter cap combusts spontaneously, igniting in turn the propulsive charge that otherwise would have ignited at a temperature from 320.degree. C. to 400.degree. C. After the propulsive charge ignites, as during regular firing, enough pressure develops in the propulsion chamber to act on the base of the projectile eventually to rupture the mechanical connection between cartridge shell and projectile, causing them to fly apart explosively. [0009] Significant damage may result simply from the quantity of exploded propulsive charges of a large number of cartridges. However, the cartridge shell and projectile may cause great damage while flying apart. Cartridge shell and projectile here act quasi as projectiles. Any receiver containers involved will be destroyed, whereby the separated cartridge shells and projectiles may endanger humans and cause major mechanical damage. [0010] During testing, such cartridges are placed into a heater, and heat is gradually supplied to the heater. After the igniter-cap ignition temperature of about 220.degree. C. is reached, as illustrated, the igniter cap and thereby the propulsive charge of the cartridges are ignited. The cartridge shell and projectile were blown apart and thrown up to 100 meters as a result of the pressure buildup in the propulsion chamber, so that the energy released when many such cartridges catch fire is considerable. OBJECT OF THE INVENTION [0011] It is the object of the invention to present measures intended to prevent separation of the cartridge shell from the projectile when there is a sharp increase in ambient temperature above the ignition temperature of the pyrotechnic igniter charge. [0012] Another object of the invention is to present measures intended to prevent damage to the environment caused by a collection of many such cartridges, e.g., in a storage or transport container, upon sharp increase in ambient temperature such as caused by a fire. [0013] Another object of the invention is to weaken the effect of the main charge after ignition of the igniter charge so that neither large pressure damage nor major mechanical damage results. [0014] Yet another object of the invention is to so configure the cartridge munition that the characteristics of the cartridge munition are not influenced by these preventive measures. DESCRIPTION OF THE INVENTION [0015] According to the invention, it is recommended that a cartridge munition consisting of a projectile and a cartridge shell, possessing a propulsion chamber to provide passages that exit from the propulsion chamber and penetrate the wall of the cartridge shell, to be filled with a solid, pressure-tight fusible filler material whose melting point is lower than the minimum ignition temperature of any pyrotechnic charge in the munition, i.e., lower than the ignition temperature of the pyrotechnic igniter charge and the propulsive charge. [0016] Such a fusible material is preferably a fusible metal. Such fusible metals include alloys of bismuth and tin, whereby other metals such as lead etc. may be included. [0017] If a cartridge of the type under discussion is heated to the melting temperature of the fusible material or metal, for example, 180.degree. C., then the fusible material in the passages within the cartridge shell that connect the propulsion chamber to the outside melts. If the temperature continues to increase and the igniter cap and thereby the propulsive charge are ignited, then no pressure may build up within the propulsion chamber because the freed passages function as pressure-relief apertures. The result is that propulsive charge merely burns, whereby the propulsive gases thus created may escape via the pressure-relief apertures. Cartridge shells and projectiles are thus not separated from each other, so that neither pressure damage nor mechanical damage may occur. [0018] This was confirmed by a test in which a large quantity of such cartridges was placed into a conventional transport box made of lead. The lead box was not damaged even once. [0019] The passages between the propulsive charge and the outside of the cartridge shell may be configured in many different ways: e.g., the housing of the igniter cap may be made of such a fusible material or metal; also, pressure-relief apertures around the igniter cap that are filled with the fusible material are a possibility. Either two or four apertures are recommended for this embodiment. Another option is to provide apertures from the propulsion chamber penetrating the sidewall of the cartridge shell. [0020] However configured, the passages must be so shaped that during a normal shot of the projectile out of the cartridge shell, the fusible material withstands the high pressures within the propulsion chamber. Resistance to pressure may be increased by configuring the passages to be conical, decreasing toward the outside, as stepped or threaded holes, etc. Continue reading... Full patent description for Cartridge munition, particularly one of medium caliber Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Cartridge munition, particularly one of medium caliber patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Cartridge munition, particularly one of medium caliber or other areas of interest. ### Previous Patent Application: Methods and apparatus for projectile data link system Next Patent Application: Xm-5866 stingball flashbang grenade Industry Class: Ammunition and explosives ### FreshPatents.com Support Thank you for viewing the Cartridge munition, particularly one of medium caliber patent info. 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