Patent Application
20100275804
The present invention relates generally to novel cartridges for use in weapons of various types. More specifically, the present invention relates to a novel ammunition cartridge structure using a plastic casing, and a method for manufacturing the plastic casing.
Heretofore, ammunition casings have been manufactured primarily by using brass. However, the use of brass casings for ammunition has several significant drawbacks. First, the use of brass is costly, particularly when copper is in short supply, and that cost is passed along to the consumer. Secondly, the brass component of bullets adds significant weight to the bullet, which creates a significant burden to those who must carry large amounts of ammunition, particularly including hunters, members of the military, and law enforcement. Additionally, in order to prevent the deleterious effects that high humidity and other extreme environmental conditions may have on ammunition over time, costly protective measures must be adopted.
To overcome these disadvantages, other plastic bullet cases have been proposed, but each effort has resulted in its own set of problems. Some plastic casings have failed because the plastic component could not withstand the high temperatures associated with repeated, rapid firings, thus resulting in a melting or softening of the plastic during use. Other plastic ammunition casings are not strong enough to withstand the violent extraction action of the weapon, so that the casing fails structurally and fragment as it is being ejected from the weapon, which causes fragments of the casings then become lodged in the weapon. Further, many of the plastic casings that have been proposed include complicated designs requiring multiple, time consuming manufacturing steps. Thus, the plastic casings proposed to date have significant disadvantages, and have not been adopted on a mass commercial scale.
Therefore, it would be desirable to provide a method of producing a non-metallic, preferably plastic, ammunition casing that is simple and inexpensive to manufacture. Additionally, it would be desirable to provide a plastic ammunition casing using a polymeric material that has a high enough melting temperature to withstand the heat produced during the rigors of rapid automatic fire, and that is strong enough to be extracted from an automatic weapon without suffering structural failure. Such plastic bullet casings would provide a reduction in cost of training and combat ammunition, reduction in weight of ammunition with consequent logistic advantages, improved reliability, and reduced weapon jamming problems.
In accordance with one aspect of the invention, ammunition is provided for use in connection with hand guns, rifles, semi-automatic and automatic weapons, machine guns, and the like, in which the casing is made from a polymeric material having a high melting point temperature and high structural integrity. Preferred materials used in the manufacture of the casing include polyphenylene sulfide containing fiberglass or polycarbonates. Other materials may be used, including nylons, polyethylene, polypropylene, and PET, among others. The shape of the casing, in one embodiment, is generally the same shape as ammunition having a brass casing, including a tubular body, an open end for receiving a projectile, and a substantially closed end having an annular groove around the periphery of the body at a lower end, thus defining an annular rim. An aperture is provided at or near the center of the substantially closed end for insertion of a primer cap.
The plastic casing may be manufactured by injection molding, preferably with a center gate to prevent knit lines. After the plastic casing has been formed, the primer cap is inserted into the aperture in the closed end, the propellant is placed within the tubular body and positioned adjacent the primer cap, and the projectile is fitted and secured into the open end of the tubular body of the casing, completing the process. It should be understood that the specific size and shape of the casing may be modified in accordance with the specifications of the weapon for which the ammunition is being manufactured, including the caliber, the end use, and desired effect contemplated for the projectile.
These types of plastic casings may used in conjunction with pistol, rifle and shotgun ammunition. It is contemplated that the instant plastic ammunition casings may be used for rounds of many different calibers and shapes, as well as for target rounds and blanks.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
A first embodiment of a plastic casing for ammunition is shown in
As shown in
With respect to the propellant 34 used herein, a variety of propellant charge types are well known and can be considered to broadly include all suitable types of charges, including conventional propellant charges (gunpowder) and conventional explosive charges such as PYRODEX, a smokeless black powder substitute available from Hodgdon Powder Co., Inc. Shawnee Mission, Kans.
The projectile 30 may be any standard projectile formed from lead or other suitable materials. In one embodiment, the projectile 30 is formed of zinc or a zinc alloy, preferably die cast, and preferably having a copper jacket around the outside of the projectile. This arrangement avoids the use of lead, which is prohibited in many indoor shooting ranges.
In a preferred embodiment, the plastic casings are made from polyphenylene sulfide containing fiberglass or polycarbonate. However, other polymeric materials may be used, including nylon, polyethylene, polypropylene and PET, among others. The preferred method of manufacture for the plastic casings is injection molding, although other methods are contemplated, including milling. In the injection molding process, center gates may be utilized to prevent knit lines, thereby increasing the structural integrity of the casing 1O.
In another embodiment, an ammunition blank having a tapered casing configuration to be used in conjunction with rifles is provided, as shown in
The plastic casing 10 includes, in a preferred embodiment, a first tapered section 44, and a second tapered section 46 toward the tip 50. A straight cylindrical section is disposed between the first tapered section 44 and the second tapered section 46. It is contemplated that a projectile (not shown) may be included within the tip 50 of the casing 10.
This tapered plastic casing may also be integrally formed through an injection molding process, and then the primer cap 26 and the propellant 34 are added to form the final product. This arrangement allows the plastic casings to be used for ammunition having different shapes (particularly tapered shapes) and sizes.
It is also contemplated that integrally formed, polymeric casings may be used for shotgun shells, as shown in
One advantage to using plastic or polymeric materials to form different types of ammunition casings is that different colorants may be added to the plastic to form the casings. Such an arrangement allows ammunition of different calibers to be color coded, so that ammunition of one caliber might be blue, while ammunition of another caliber might be red, yellow or clear, for instance. Additionally, it is contemplated that spent plastic casings may be recycled. After the spent primer caps are removed from the spent casings, the casings may be recycled into new casings, or into any other product that uses the material from which the casings are manufactured.
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein. All features disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
