Ammunition and explosives – Cartridges – Case
Reexamination Certificate
2001-09-12
2003-01-07
Carone, Michael J. (Department: 3641)
Ammunition and explosives
Cartridges
Case
C102S204000, C102S443000, C102S430000
Reexamination Certificate
active
06502514
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of firearms and, more specifically, to the field of firearm cartridges.
BACKGROUND OF THE INVENTION
A cartridge provides ammunition for a firearm. It normally includes a casing, a projectile associated with the casing, an ignitable propellant that when ignited propels the projectile away from the casing through the barrel of the firearm, and a primer that ignites the propellant. The ignitable propellant ordinarily ignites upon the application of heat as with, for example, ordinary gunpowder (i.e., potassium nitrate, wood charcoal, and sulfur in the approximate proportions of 6:1:1 by mass). The propellant responds to heat by suddenly forming hot expanding gases that causes a contained explosion that propels the projectile from the firearm. The primer normally is a percussion impact or pressure sensitive compound that ignites in response to shock or pressure. In firing, a striker or firing pin usually a small rod or hammer causes a shock and/or pressure that ignites the primer. When ignited, the primer expels hot particles or gas. The heat generated by ignition of the primer in turn ignites the propellant causing the sudden formation of hot expanding gases result in the contained explosion that propels the projectile from the firearm.
The cartridge combines into a single self-contained system each of the elements that must be included either as part of the ammunition or the firearm itself for successful firing. By contrast, each of these elements had to be separately loaded in flint-lock and percussion cap firearms which were the only available firearms up through the middle of the nineteenth century. By incorporating each of these items in a stand-alone, easily loaded module, the cartridge has made the firearm more potent and more practical. The cartridge has been perhaps the most important factor contributing to the advances in small arms technology that began in the latter half of the nineteenth century.
Notwithstanding its significant advantages, problems with the conventional firearm cartridge remain. Foremost among these is the risk that the ignitable substance forming the primer will fail. For example, a defect in the manufacture of the substance might render it inoperable before it is positioned within the cartridge casing. Even if the primer substance is free of defect and operable when first put into the cartridge, there remains the risk that it might later be rendered inoperable. For example, moisture could enter the portion of the cartridge where the primer is placed. The possibility that this might occur is higher the more harsh the conditions under which the firearm and cartridge are used such as in a wet or swampy area. Because the primer is most efficiently placed near the proximal end surface of the cartridge casing, there is a greater possibility the primer will be damaged than will the propellant, which is ordinarily ensconced in a medial portion of the casing between the projectile and the proximal end of the casing.
Because, again, the primer is positioned most efficiently near the proximal end surface of the cartridge there also is the risk that rather than moisture seeping in, the primer substance could seep out due to a small hole or other defect in the casing. Whatever, the cause, the fact remains that if the primer substance is or becomes inoperable, the cartridge will misfire or far more likely not fire at all. The later is commonly referred to as cold shot. Specifically, if the primer substance, for whatever reason, is inoperable, the primer will not ignite and, hence, neither will the propellant, thus leading to a failure of the firearm to fire.
There have been efforts to address some of the firing problems inherent in conventional firearm cartridges. For example, U.S. Pat. No. 5,148,749 to Maes et al., titled Priming Chamber For A Firearm Cartridge. Maes et al., attempts to improve the conveyance of heat from a primer chamber to a main charge (i.e., powder) in the cartridge by positioning an anvil and flash holes in the primer chamber. Maes et al., however, fails to address the problems associated with misfire as described above. U.S. Pat. No. 4,378,739 to Klein et al., titled Primer Firing Means, does attempt to enhance firing reliability, but requires the replacement of a firing pin mechanism with use of a shockwave, high-pressure gas that is propelled by a detonating chord. Thus, the Klein et al. device is unworkable in the context of a standard firearm which fires a cartridge having a casing and a projectile positioned at least partially therein and which requires detonation using a firing pin.
In an unrelated context, U.S. Pat. No. 1,491,000 to Brandt et al., titled Torpedo, suggests an improvement to the fuse used to launch a torpedo. Brandt et al. attempts to reduce the possibility of cold shot by using two primer caps. Upon detonation, each primer cap releases heat or pressure which is then conveyed along angled passageways to a central tube and onward to the end of the tube where there is positioned an ignitable substance adapted to blow out an end cap and ignite a slow burning fuse. The primer caps are ignited when struck by a multi-pronged striker that, until firing, remains spaced apart from the primer caps. The features of Brandt et al., like those of Klein et al., however, are ill-suited for adaption to a firearm. The features which may work well for a torpedo pose distinct disadvantages for the cartridge of a firearm. Among these are the specific primer cap detonator that must be used. The multi-pronged structure is more complicated and costly to manufacture, while the need to space it apart from the caps to be detonated slows down firing time. The problem of slowed firing time, moreover, is exacerbated by the fact that the device also relies on a slow burning fuse for firing.
Moreover, Brand et al. presents other features that themselves can increase the risk of cold shot. Specifically, the indirect conveyance of heat from the primer caps via angled passages that must merge into a single long tube not only further reduces firing time, but also presents the risk that particles may lodge at one of the bends of the angled passages. If the lodged particles clog the single tube, there is no alternative means of conveying the heat needed for firing. If this occurs, the result is a cold shot.
In light of these limitations on other devices, there remains a significant need for a cartridge usable with a standard firearm that provides reduced delay in detonation and enhanced reliability in firing.
SUMMARY OF THE INVENTION
With the foregoing in mind, the present invention advantageously provides a multi-ignition cartridge that has substantially reduced chances for misfire and cold shot. The multi-ignition cartridge, moreover, further provides for rapid firing by ensuring that the time lapse between impact of the firearm's firing pin of the firearm's on the multi-ignition cartridge and the firing of a projectile from the cartridge is kept to a minimum. Moreover, the multi-ignition cartridge achieves these distinct advantages while nonetheless being relatively easy and cost efficient to manufacture.
According to the present invention, the multi-ignition cartridge includes a cartridge casing and at least one projectile adapted to be positioned at least partially within the casing. The cartridge casing further includes at least two separate chambers formed in the casing. Each chamber, moreover, is in fluid communication with a separate interior cavity formed in the cartridge and in which the at least one projectile can be at least partially contained. The outer surfaces of each chamber form portions of the surface of the cartridge casing. A strike plate is positioned to contact each surface portion corresponding to each chamber. Preferably, the strike plate abuttingly contacts each surface portion.
Each separate chamber contains an ignitable substance. When the strike plate is struck by the firearm's firing pin, the strike plate rapidly compresses the outer surface p
Allen Dyer Doppelt Milbrath & Gilchrist, P.A.
Carone Michael J.
Semunegus Lulit
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