Abstract:
A compressed gas firearm is capable of firing either cartridges filed with pellets, or solid unitary projectiles. The firearm includes a barrel that is hinged to the butt so that cartridges or an adapter can be inserted into the end of the barrel. A compressed gas chamber in the butt is capable of releasing compressed gas against the rear of the cartridge or adapter to fire the pellets or the unitary projectile. When the adapter is inserted into the barrel, a projectile can then be inserted into the adapter before the barrel is closed for firing. Indentations may be formed in the rear of the barrel to facilitate removal of the cartridges or adapter.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The disclosure relates to a compressed gas operated firearm. More particularly, the disclosure relates to a firearm that is capable of firing pellets or a solid projectile. 
         [0003]    2. Background 
         [0004]    U.S. Pat. No. 34,806, dated 1862, discloses a method of forming fixed charges of shot which can then be used in a firearm with or without wrappers. The method involves putting shot pellets in a mold, and pouring among the shot, while in a mold, some easily-fusible material such as ace grease, stearine, etc. Upon cooling, the material will fix the shot, and, when discharged from the mold, will retain said shot in the form it assumed in the mold. 
         [0005]    U.S. Pat. No. 2,368,029, dated 1941, discloses a shot shell having a metallic base and a cylindrical casing attached to the base. A propellant charge is put in the base, and a projectile charge is placed in the cylindrical casing. Means are provided to separate the propellant charge in the base from the projectile charge in the casing. Such means comprising a series of driving wads, an overshot wad associated with the end of the casing and adapted to retain the projectile charge in the casing and tracer projectiles attached to the outer surface of the overshot wad. 
         [0006]    U.S. Pat. No. 5,979,330, dated 1998, discloses a shotgun shell wad that is used in a shotgun shell. Three discs disposed within the generally cylindrical tubular wall define a seal gas section, a middle section, a shot cup extension section, and a shot cup section. The third disc, which separates the shot cup extension section and the shot cup section, is detachably connected to the tubular wall such that when the shell is fired, the third disc breaks away and travels rearward relative to the rest of the shot shell wad to a position adjacent to the second disc. A plurality of fingers defined by a plurality of lateral cuts through the tubular wall in the shot cup section extend from a point in the shot cup section to the forward tubular end of the wall. The wall also includes a plurality of cuts passing therethrough lateral substantially at the point where the plurality of cuts terminate. Circumferential, the plurality of cuts extend through a section of each of the plurality of fingers. A plurality of lateral ridges extend inwardly from the tubular wall from substantially the point where the plurality of lateral cuts terminate to substantially the forward tubular end of the wall and are positioned at substantially the to center of each of the plurality of fingers. 
         [0007]    The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The embodiments will be described in detail with reference to the following drawings, in which like reference numerals refer to like elements, and wherein:  FIG. 1  is a partial perspective view of a firearm; 
           [0009]      FIG. 2  is a sectional view taken along section line II-II of  FIG. 1  with an un-fired pellet cartridge loaded in the firearm; 
           [0010]      FIG. 3  is sectional view taken along section line II-II of  FIG. 1  after the pellet cartridge has been fired; 
           [0011]      FIG. 4  is a sectional view taken along section line II-II of  FIG. 1  showing the use of an adapter for firing a solid projectile; 
           [0012]      FIG. 5  is a top perspective view of a pellet cartridge; 
           [0013]      FIG. 6  is a bottom perspective view of the pellet cartridge shown in  FIG. 5 ; 
           [0014]      FIG. 7  is a top perspective view of another embodiment of a pellet cartridge; 
           [0015]      FIG. 8  is sectional perspective view of the pellet cartridge shown in  FIG. 7  taken along section line VIII-VIII; 
           [0016]      FIG. 9  is a perspective view of an adapter which can be used to fire a solid projectile; and 
           [0017]      FIG. 10  is a partial perspective view of the firearm in an opened condition so that a pellet cartridge or an adapter and solid projectile can be loaded into or removed from the rifle. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The firearm disclosed in this application can be used to file pellets or solid projectiles. The pellets would be loaded into a pellet cartridge similar to a typical shotgun shell. When such a pellet cartridge is used, the firearm would operate much like a traditional shotgun, although the pellets would be propelled by compressed gas, instead of an explosive charge. 
         [0019]    The same firearm can also be used to fire solid projectiles. An adapter would be used to fire a solid projectile. The adapter would resemble a typical shotgun shell, and the adapter would be loaded into the barrel of the firearm in the same basic manner as the pellet cartridge. 
         [0020]      FIG. 1  shows the barrel, trigger and butt portions of the firearm  1 . The firearm  1 , includes a butt  5  located behind the trigger and trigger guard.  FIGS. 2-4  show cross sectional views, taken along section line II-II, which illustrate the interior mechanisms of the firearm 
         [0021]    As shown in  FIG. 2 , a pellet cartridge  2  can be loaded into the firearm. This would be accomplished by breaking open the firearm as shown in  FIG. 10 . The pellet cartridge  2  would be inserted into a hole  10  at the rear of the barrel. The barrel would then be closed back into the configuration shown in  FIGS. 1 and 2 . 
         [0022]    A typical cylindrical pellet cartridge, as shown in  FIG. 8 , includes a plurality of pellets  7  trapped between a rear cover  3  and a front cover  8 . A rear hoop  20  is located at the back end of the cartridge  2  to limit the depth to which the pellet cartridge can be inserted into the barrel of the rifle. The front cover  8  divides the interior of the cartridge into a first space  11 , where the pellets  7  are located, and a second space  12  at the front of the cartridge. In some embodiments, as shown in  FIGS. 5 and 6 , an expanded diameter cylindrical portion  13  is attached to the exterior rear of the cartridge. 
         [0023]    A barrel  6  of the firearm ends at a widened portion  24  located at the end  10  of the barrel  6 . The widened portion  24  could receive the rear hoop  20  of the pellet cartridge. The widened portion  24  may also be shaped to accommodate the expanded diameter cylindrical portion  13  of the pellet cartridge shown in  FIGS. 5 and 6 . 
         [0024]    A compression chamber  4  is formed in the butt  5 . Compressed gas in the compression chamber  4  is used to eject the pellets from the cartridge and down the barrel  6 . When the firearm is fired, the compressed gas presses against the rear cover  3 . The rear cover deforms and advances into the interior of the cartridge and presses the pellets forward against the front cover  8 . The front and rear covers can be made of glass, plastic, paper or other suitable materials. 
         [0025]    In embodiments that do not use extremely large pressures, the cartridge shown in  FIGS. 7 and 8  can be used. In other embodiments, where highly pressurized gas is used, a cartridge like the one shown in  FIGS. 5 and 6  can be used. The pellet cartridge shown in  FIGS. 5 and 6  includes the expended diameter outer portion  13  which acts to reinforce the cartridge. If the reinforcing were not used, the pressure of the gas could cause the rear end of the pellet cartridge to expand outwards. The exit speed of the pellets can average 180 m/s, depending on the pressure of the gas and the weight and size of the pellets. 
         [0026]    Note, the front cover  8  is spaced back from the front edge of the cartridge. As a result, the front cover  8  separates the interior of the cylindrical cartridge into the first space  11  for receiving the pellets  7  and the second space  12 . When the rifle is fired, the second space  12  guides the pellets  7  as they begin to move, and before they reach the interior of the barrel  6 . 
         [0027]    The movement of the pellets  7  also forces the front cover  8  to move down the length of the cartridge. Before the rifle is fired, the front cover  8  is attached to the interior cylindrical wall of the cartridge at two or more points  14 . In preferred embodiments, the front cover is attached to the interior wall of the cartridge at three points. The attachment between the front cover and the cylinder acts to contain the pellets within the cartridge. But the front cover is also well attached to the cartridge so that a relatively large amount of pressure must build up behind the pellets before the front cover will break away and allow the pellets to travel down the barrel of the rifle. This helps to ensure that the pellets are ejected at a sufficiently high rate of speed. 
         [0028]    The rear cover  3  also passes down the length of the cartridge when the rifle is fired. The movement of the rear cover down the length of the cartridge ensures that all of the pellets  7  within the cartridge are ejected. As shown in  FIG. 3 , when the rifle is fired, the front cover  8 , pellets  7  and rear cover  3  all travel down the barrel and are ejected together. Because the pellets and front and rear covers travel down the barrel together, the pellets follow a substantially straight path down the barrel. This, in turn, tends to result in the pellets continuing to follow a straight path after they have been ejected from the barrel. 
         [0029]    Once the rifle has been fired, and the user needs to replace the spent cartridge with a new one, the firearm is opened as shown in  FIG. 10 . First notches  9  are formed on the rear of the barrel to make it easy for the user to grasp the left and right sides of the rear hoop  20  at the back of the cartridge. Second notches  22 , are cut into the larger first notches  9  to make it even easier for the user&#39;s fingers to get behind the rear hoop  20  of a cartridge to facilitate extraction of the cartridge from the barrel. The first notches  9  and second notches  22  have a crescent shape, which corresponds to the shape of a user&#39;s fingers, to facilitate extraction of a cartridge  2   
         [0030]    As mentioned above, the rifle can also be used to fire solid projectiles using an adapter like the one shown in  FIG. 9 . To operate the firearm in this manner, the barrel would be opened as shown in  FIG. 10  and the adapter  16  would be inserted into the barrel. As shown in  FIG. 4 , a slug-like projectile  17  would then be inserted into the adapter  16 . The barrel would then be closed and would be ready to fire. 
         [0031]    As with the pellet cartridges described above, the adapter could include an additional reinforcing portion  18  which would be accommodated by the widened portion  24  at the rear of the barrel  6 . The front end of the adapter would be beveled to make it easier to insert the adapter into the barrel  6 . Typically, the adapter would be made of metal or a metal alloy. The adapter  16  may also include an outer hoop  19  that would further improve its fixation in the interior of the barrel  6  to keep the adapter mounted within the barrel when the barrel is open. 
         [0032]    Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
         [0033]    Although a number of illustrative embodiments have been described, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. 
         [0034]    More particularly, various variations and modifications are possible in the component parts and/or arrangements which would fall within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.