Abstract:
A projectile assembly that enables a compressed gas powered projectile to be fired from a traditional ammunition firearm. The projectile assembly includes a casing that is shaped like the casing of traditional ammunition. A projectile is set into the tip of the casing. Within the casing is located a compressed gas cartridge. The projectile assembly is loaded into the breech of a traditional firearm. Once the firearm is fired, the firing pin of the firearm strikes a piercing pin within the casing. The piercing pin, in turn, strikes and pierces the compressed gas cartridge. The gas pressure displaces the projectile from the tip of the casing and propels the projectile down and out the barrel of the firearm. The casing is designed so that a new compressed cartridge can be placed in the casing and the projectile replaced.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to ammunition that is fired from firearms. More particularly, the present invention relates to non-lethal ammunition that is fired from a firearm using compressed gas rather than gunpowder. 
     2. Prior Art Statement 
     In the prior art, there are many different types of guns that fire projectiles using the power of compressed gas rather than the power of an explosive, such as gunpowder. The most common examples of such prior art guns would be BB guns and paintball guns. Compressed gas is typically used in guns where it is desired to fire a projectile at subsonic speeds. Furthermore, compressed gas does not have the explosive power of gunpowder. Consequently, guns that used compressed air can be made flimsier and far less expensively than guns that fire traditional gunpowder powered bullets. 
     Guns that fire projectiles using compressed gas typically obtain the compressed gas from one of three sources. The first source is a manual pump. Manual pumps are used to compress air within the structure of the gun. It takes a significant amount of work to compress a small amount of air. Consequently, manual pumps are often used on BB guns, where only a small amount of compressed air is needed to fire a small, lightweight projectile. 
     The second type of compressed gas source is a powered compressor. Powered compressors can produce large volumes of compressed air in a relatively small time. As such, powered compressors are often used to power nail guns and other equipment that requires a large volume of compressed air to operate. However, powered compressors are very large and heavy. As such, a person cannot readily carry them from place to place. Powered compressors are therefore limited to applications where a gun is only going to be fired in a single location. 
     The third type of compressed gas source is a compressed gas canister. Canisters can be filled with compressed air, or other non-combustible gases, such as carbon dioxide or nitrogen. The compressed gas canisters can then be attached to the gun and used to power the gun. 
     Compressed gas canisters differ widely in size, shape, composition and weight. One of the smallest widely commercially available compressed gas canisters is the twenty-gram CO2 cartridge. A twenty-gram CO2 cartridge is a metal canister that is filled with twenty grams of liquid carbon dioxide. The twenty-gram CO2 cartridge has a neck that is sealed with a piercable membrane. When the piercable membrane is ruptured, the pressurized contents of the twenty-gram CO2 cartridge are released. 
     Since the twenty-gram CO2 cartridge is the smallest and cheapest readily available compressed gas source, it has been used to power a wide variety of guns. Many pellet guns, BB guns and paintball guns utilize twenty-gram CO2 cartridges. With such prior art guns, a twenty-gram CO2 cartridge provides enough compressed gas to fire between five and twenty five shots. 
     However, in the prior art, there are guns that utilize all the gas in a twenty-gram CO2 cartridge in a single shot. In one type of prior art gun, the gun merely pierces the twenty-gram CO2 cartridge and the cartridge itself becomes the projectile that is fired from the gun. Such prior art guns are exemplified by U.S. Pat. No. 5,652,405 to Rakov, entitled System For Shooting Using Compressed Air, and U.S. Pat. No. 5,909,000 to Rakov which is also entitled System For Shooting Using Compressed Air. 
     In other prior art guns, the twenty-gram CO2 cartridge is used to project a single secondary projectile from a gun. For instance, in U.S. Pat. No. 2,964,031 to Dotson, entitled Underwater Gun And Projectile For Spear Fishing, a twenty-gram CO2 cartridge is used to fire the harpoon of a spear gun. 
     Regardless of whether a gun fires multiple shots from a CO2 cartridge or a single shot, most all of the prior art guns that utilize CO2 cartridges are specialized guns that are designed to specifically receive the CO2 cartridge. Such prior art guns cannot be used to fire traditional gunpowder powered ammunition. Accordingly, if a policeman or a serviceman wants to use a compressed gas gun to fire smoke grenades or some other non-lethal projectile, they must carry a dedicated gun for that purpose. If they still desire to be armed with their traditional firearm, they must carry two guns. 
     A need therefore exits for a projectile system that enables a non-lethal compressed gas powered projectile to be fired from a traditional firearm, without requiring modifications to that traditional firearm. In this manner, a person can change between firing traditional gunpowder based ammunition to firing compressed air powered ammunition without having to change guns. This need is met by the present invention as described and claimed below. 
     SUMMARY OF THE INVENTION 
     The present invention is a projectile assembly that enables a compressed gas powered projectile to be fired from a traditional ammunition firearm. The projectile assembly includes a casing that is shaped like the casing of traditional ammunition. A projectile is set into the tip of the casing. Within the casing is located a compressed gas cartridge. The projectile assembly is loaded into the breech of a traditional firearm. Once the firearm is fired, the firing pin of the firearm strikes a piercing pin within the casing. The piercing pin, in turn, strikes and pierces the compressed gas cartridge. Once the compressed gas cartridge is ruptured, the pressure within the casing increases dramatically. The gas pressure displaces the projectile from the tip of the casing and propels the projectile down and out the barrel of the firearm. The remaining spent casing is ejected from the firearm in a traditional manner. The casing is designed so that a new compressed cartridge can be placed in the casing and the projectile replaced. As such, the same casing can be used numerous times and can be used to fire a variety of projectiles. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is made to the following description of an exemplary embodiment thereof, considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of an exemplary embodiment of a projectile assembly in accordance with the present invention; 
     FIG. 2 is a selectively fragmented and exploded view of the projectile assembly shown in FIG. 1; 
     FIG. 3A is a cross-sectional view of the projectile assembly shown prior to being fired; 
     FIG. 3B is a cross-sectional view of the projectile assembly shown while being fired; and 
     FIG. 3C is a cross-sectional view of the projectile assembly shown after it has been fired. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     There are many different types of firearms that fire traditional gunpowder powered ammunition. These firearms come in a wide variety of shapes, sizes, styles and designs. The size of the projectile fired by such firearms is typically referred to as the caliber of that firearm. Depending upon the model of the firearm, the caliber of the firearm is equal to the diameter of the bore in the barrel of the firearm. That diameter may be defined either in millimeters or the percentages of an inch. For instance, a firearm with a nine millimeter caliber has a barrel bore of nine millimeters. A firearm that is forty-five caliber would have a barrel bore that is {fraction (45/100)}ths of an inch, or 0.45 inches. 
     The present invention projectile assembly can be manufactured in any desired caliber. However, as will be explained, the present invention projectile assembly preferably contains a standard twenty-gram CO2 cartridge within its structure. Twenty-gram CO2 cartridges have a diameter of approximately 0.72 inches. Accordingly, to utilize conventional twenty-gram CO2 cartridges, the present invention projectile assembly is preferably made to be fired from large bore firearms that fire ammunition in excess of 72 caliber or 14.8 millimeters. Such firearms include, but are not limited to, twelve-gauge shotguns, grenade launchers, and flair-guns. 
     Referring to FIG. 1, an exemplary embodiment of the present invention projectile assembly  10  is shown. The projectile assembly  10  has a projectile  12  that is mounted to the tip of a casing  14 . However, as will later be explained, the casing  14  does not contain gunpowder. Rather, the casing contains a twenty-gram CO2 cartridge. The projectile assembly  10  is placed into a firearm that normally fires gunpowder powered ammunition. The present invention projectile assembly  10  mimics the shape of the gunpowder powered ammunition and even contains a base ridge  16  that is used by a firearm to eject a spent casing after it has been fired. 
     When fired, the projectile  12  is propelled from the casing  14  at subsonic speeds. As such, the projectile  12  travels at non-lethal speeds from the firearm. Accordingly, rubber projectiles, for use in riot control, and other crowd control projectiles can be adapted for use as part of the present invention. Projectiles, such as smoke grenades, tear gas grenades, flares and other large projectiles that are designed to be fired at subsonic speeds can also be used. 
     Referring now to FIG. 2, it can be seen that the projectile assembly  10  has multiple parts that are all contained within the casing  14 . The casing  14  is a two part assembly, having a top section  20  and a bottom section  22 . The bottom section  22  of the casing  14  contains the base ridge  16  that is used by a firearm to eject the casing  14  after it has been fired. The top section  20  of the casing  14  holds the projectile  12 . The bottom section  22  of the casing  14  engages the top section  20  of the casing  14  with a threaded coupling. As such, the top section  20  of the casing  14  and the bottom section  22  of the casing  14  can be selectively connected and disconnected, thereby providing easy access to the interior of the casing  14 . 
     The bottom section  22  of the casing  14  has a bottom base  26 , wherein the walls of the casing  14  extend in a cylindrical configuration up from the bottom base  26 . The exterior of the casing  14  is inset immediately before the bottom base  26 , thereby forming the base ridge  16 . An aperture  28  is formed in the center of the bottom base  26 . As will be understood, the aperture  28  corresponds to the point where the firing pin of a firearm will strike the projectile assembly  10  when the projectile assembly is fired from a gun. The bottom section  22  of the casing  14  has internal threading in two areas. The first area of internal threading  29  extends upwardly from the bottom base  26  within the center of the bottom section  22 . The second area of threading  30  is immediately adjacent the top edge of the bottom section  22  of the casing  14 . 
     A piercing pin  32  is provided. The piecing pin  32  has an enlarged head  34  that rests in the aperture  28  in the bottom base  22  of the casing  14 . The head  34  of the piercing pin  32  extends into the aperture  28  but is too large to pass through the aperture  28 . A sharpened point  36  extends from the enlarged head  34  and faces vertically toward the interior of the casing  14 . The head  34  of the piercing pin  32  is biased down against the aperture  28  at the bottom of the casing  14  by a return spring  38 . 
     The return spring  38  is held in place by a threaded plug  40 . The threaded plug  40  is.comprised of a hollow cylindrical section  42  and a platform  44  that is disposed on top of the cylindrical section  42 . Grooves  45  are formed on the top of the platform for a purpose that will later be explained. An aperture  46  is disposed in the center of the platform that communicates with the center of the cylindrical section  42 . The return spring  38  is set into the center of the cylindrical section. 42 . The piercing pin  32  is then placed atop the return spring  38 . When pressed against the return spring  38 , the sharpened point  36  of the piercing pin  32  extends through the aperture  46  in the platform  44 . However, without a bias sufficient to deform the return spring  38 , the sharpened point  36  of the piercing pin  32  does not extend through the aperture  46  in the platform  44 . 
     The exterior of the cylindrical section  42  of the threaded plug  40  contains threads  47 . These threads  47  engage the first area of internal threading  29  within the bottom section  22  of the casing  14 . When engaged with the bottom section  22  of the casing  14 , the return spring  38  becomes partially compressed and biases the head  34  of the piercing pin  32  against the aperture  28  in the base of the bottom section  22  of the casing  14 . 
     The top section  20  of the casing  14  is tubular in shape. A threaded recessed region  50  is located near the bottom edge of the top section  20 . The threaded recessed region  50  engages the second area of internal threading  30  of the bottom section  22  of the casing  14 . When the top section  20  of the casing  14  is threaded into the bottom section  22  of the casing  14 , the diameter of the overall casing  14  remains constant across the transition from the top section  20  of the casing  14  to the bottom section of the casing  14 . 
     A baffle wall  52  is disposed within the top section  20  of the casing  14 , thereby dividing the top section  20  of the casing  14  into two internal areas  53 ,  54 . The baffle wall  52  is perforated. The area  53  above the baffle wall  52  receives the base of the projectile  12 . The area  54  below the baffle wall  52  receives a compressed gas cartridge  60 . The preferred compressed gas cartridge  60  is a twenty-gram CO2 cartridge that has an external diameter of approximately 0.72 inches. Accordingly, to receive a twenty-gram CO2 cartridge, the interior of the top section  20  of the casing  14  must be at least 0.72 inches wide. 
     If the projectile assembly  10  is being fired from a twelve-gauge shotgun or another firearm that has a bore caliber only slightly wider than that of the compressed gas cartridge  60 , then the compressed gas cartridge  60  can be directly placed into the top section  20  of the casing  14 . The top section  20  of the casing will then support the compressed gas cartridge  60  in a vertical orientation. However, if the present invention projectile assembly  10  is being manufactured for a firearm having a bore caliber that is significantly larger than the diameter of the compressed gas cartridge  60 , then an optional spacing collar  56  can be placed around the compressed gas cartridge  60 . The spacing collar  56  is a tubular structure that has an interior diameter that matches the exterior diameter of the compressed gas cartridge  60 . On the outside of the spacing collar  56  are ribs  58 . The ribs  58  extend outwardly to a diameter that matches the diameter of the interior of the top section  20  of the casing  14 . The ribs  58  also enable gas to pass between the interior of the top section  20  of the casing  14  and the spacing collar  56 , for a reason that is later explained. 
     When a compressed gas cartridge  60  is placed into the top section  20  of the casing  14  and the top section  20  of the casing  14  is attached to the bottom section  22  of the casing  14 , the piercable membrane on the compressed gas cartridge  60  rests on the top of the threaded plug  40  directly over the; aperture  46  in the platform  44 . 
     Referring to FIG. 3A, it can be seen that a gap  62  exists between the baffle wall  52  and the bottom of the projectile  12 , when the projectile  12  is seated in the casing  14 . The overall projectile assembly  10  has the same shape and appearance, as does traditional gunpowder powered ammunition. The projectile assembly  10  can therefore be loaded into any conventional firearm having the appropriate barrel bore size and breech. 
     Referring to FIG. 3B, it can be seen that when the firing pin  70  of a firearm strikes the piercing pin  32 , the piercing pin  32  deforms the return spring  38  and the piercing pin  32  punctures the compressed gas cartridge  60 . Once punctured, the compressed gas within the compressed gas cartridge  60  flows out through the puncture hole. The grooves  45  (FIG. 2) in the platform  44  of the threaded plug  40  enable the gas to flow unobstructed into the interior of the casing  14 . The gas flows around the compressed gas cartridge, utilizing the spaces between the ribs  58  of the spacing collar  56 . Finally, the compressed gas flows through the baffle wall  52  and fills the gap below the projectile  12 . The gas pressure increases under the projectile  12  until the projectile  12  is forced out of the casing  14 . Referring to FIG. 3C, the projectile  12  is then displaced from the casing  14  and fired down the barrel of the firearm. Depending upon the mass of the projectile and the bore of the firearm, muzzle velocities of between 100 feet per second and 800 feet per second can be achieved utilizing the compressed gas contained in a twenty gram CO2 cartridge. 
     From FIG. 3C, it can be seen that once the projectile  12  is fired, the return spring  38  returns the piercing pin  32  to its original orientation. Since the spent casing  14  has the same shape as a traditional ammunition casing, the spent casing  14  can be ejected from the firearm utilizing the ejection mechanisms of that firearm. However, once the spent casing is ejected from the firearm, it need not be discarded. Rather, a new projectile can be pressed into the casing  14 . The top section  20  of the casing  14  can then be detached from the bottom section  22  of the casing  14  and the new unused compressed gas cartridge can be placed into the casing  14 . The projectile assembly  10  is then ready to be reused. Accordingly, each time the present invention projectile assembly  10  is fired, only the projectile  12  and the compressed gas cartridge  60  need to be replaced before the projectile assembly  10  is ready to be fired again. 
     It will be understood that the embodiment of the present invention described and illustrated is merely exemplary and a person skilled in the art can make many variations to the shown embodiments. For example, the outer diameter of the projectile assembly can be made to be any size greater than 0.72 inches. Furthermore, the size, shape and composition of the projectile can be changed to meet any requirements. The projectile can be metal, rubber, plastic, a smoke grenade, tear gas grenade, flare or the like. Lastly, the present invention assembly is shown utilizing a twenty-gram CO2 cartridge. Larger cartridges do exist. Other size cartridges can be adapted for use-as part of the present invention. All such alternate embodiments and modifications are intended to be included within the scope of the present invention as defined below in the claims.