Abstract:
A barrel assembly for a device for shooting projectiles is disclosed. The barrel assembly comprises a firing chamber with first and second openings, wherein the firing chamber is capable of holding at least two projectiles. A first projectile retention device is located at the second opening of the firing chamber. A propellant injection device injects propellant into the firing chamber through a third opening. A firing control device initiates the injection of propellant into the firing chamber, wherein at least one projectile and the projectile retention device substantially seal the second opening of the firing chamber when propellant is introduced and at least one projectile is expelled out of a barrel through the first opening of the firing chamber.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention pertains in general to the field of barrel assemblies for weapons and firearms. More particularly, the invention relates to a barrel assembly which uses a projectile and a projectile retention device to substantially seal one opening in the barrel assembly during the firing operation. 
       BACKGROUND OF THE INVENTION 
       [0002]    The use of pneumatic guns, for example, paintball guns, has grown substantially over the past 20 years. Typical pneumatic and pneumatic paintball guns control and direct the expansion of compressed gas to accelerate a projectile through a cylindrical barrel. Paintball weapons accelerate a projectile that strikes and deposits paint on a target. The weapons are used to mark an opposing combatant to simulate being shot without substantial harm to the combatant. This simulation is useful to train police, military personnel and for recreational, competitive games and simulation. In such simulations and games, weapons that can fire at a high rate of fire while retaining accuracy increase the successful marking of other opposing combatants and more accurately simulate conventional firearms. 
         [0003]    These types of weapons are not limited to paintball or BB guns. These weapons can also be used to inflict lethal or non-lethal force through the use of conventional or rubber bullets, beanbags, and projectiles filled with irritants, pungent chemical or other disorienting means. Furthermore, the guns can be used to deliver prizes (tee shirts, baseballs, etc.) at sporting events. 
         [0004]    One problem with known pneumatic guns is that they use a mechanical piston or bolt to seal the firing chamber after a projectile has been loaded into the firing chamber. This mechanical piston or bolt may damage the projectiles before they are even fired.  FIG. 1  shows a portion of a typical barrel assembly for a pneumatic gun. The barrel  10  has a firing chamber  12  from which a projectile  22  is fired out of the barrel  10  through the opening  14 . A piston or bolt  16  is used to load projectiles into the firing chamber and to block a second opening  18  in the firing chamber  12 . In operation, when the firing sequence is initiated, propellant such as air or a gas is introduced into the firing chamber  12  through an inlet valve  20 . The pressure expansion caused by the propellant causes the projectile  22  to overcome the projectile restraint  24  and be expelled through the opening  14 . To reload, the piston or bolt  16  is retracted and another projectile from the hopper  24  is moved into the firing chamber as the piston or bolt  14  is moved back to seal the second opening  18 . 
         [0005]    The physical movement of the piston or bolt  16  causes various problems. First of all, the piston or bolt  16  may rub against the projectiles as it opens and closes and introduce defects into the projectile. The defects may change the flight characteristics of the projectile which can affect the accuracy of the gun. Furthermore, a partially chambered projectile may become jammed when the piston or bolt  16  is moved to seal the opening  14 . This may even lead to the rupture of the projectile inside the gun. In addition, the piston or bolt  16  may become jammed due to a mechanical failure thereby rendering the gun inoperable. 
         [0006]    Thus, there is a need for a new barrel assembly which overcomes the problems described above with known barrel assemblies. 
         [0007]    Hence, an improved barrel assembly which reduces the problems associated with loading projectiles using a mechanical piston or bolt would be advantageous. 
         [0008]    Some of these problems are alleviated in guns with multiple projectiles in a single chamber, but then have further problems associated with reloading. This type of gun is comprised of a stack of alternating projectiles and powder. The projectiles radially expand to seal the explosion from disturbing the next charge. Each round is in a different part of the barrel stack and has a different effective barrel length which decreases consistency and accuracy. Also, the breach end of the barrel is permanently sealed. This forces the user to reload the weapon through the muzzle or the barrels may be disposable or must be reloaded back at the factory. This is very inconvenient and makes sustained automatic fire difficult to achieve. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, the present invention preferably seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solves at least the above mentioned problems by providing a barrel assembly and a method for shooting projectiles according to the appended patent claims. 
         [0010]    One objective of the present invention is to provide a chamber assembly for projectile acceleration systems that permits rapid loading, and discharge of projectiles. 
         [0011]    In particular, an objective of the present invention is to provide a chamber assembly in which multiple projectiles are loaded into a chamber wherein one or more loaded projectiles contribute to sealing of the chamber to prevent propellent force from escaping and instead to be applied to one of the projectiles to accelerate and expel the projectile from said chamber. 
         [0012]    It is a further objective of the present invention to provide a chamber assembly which allows loading of the chamber with multiple projectiles through an opening other than the muzzle. 
         [0013]    It is a further object of the present invention to permit radial flexing of the chamber wall to decrease the inner diameter of the chamber to retain one or more loaded projectiles and contribute to sealing said chamber. 
         [0014]    It is a further object of the present invention to partially or completely seal one opening of said chamber with a projectile to be expelled in a later firing cycle. 
         [0015]    An additional object of the invention is to allow for a plurality of chamber assemblies to be assembled in an array with respective loading reloading assemblies and cylindrical barrels to accuracy direct expelled projectiles. The present invention alleviates disadvantages of prior art as the inherent chamber simplicity, separate propellent, and breach loading permits high unit density and reload ability. 
         [0016]    According to another aspect of the invention, a barrel assembly is provided for a device for shooting projectiles, comprising: 
         [0017]    a firing chamber with first and second openings; said firing chamber being capable of holding at least two projectiles 
         [0018]    a first projectile retention device at said second opening of the firing chamber 
         [0019]    a propellant injection device for injecting propellant into the firing chamber through a third opening, 
         [0020]    a firing control device for initiating the injection of propellant into the firing chamber, wherein at least one projectile and said projectile retention device substantially seal the second opening of the firing chamber when propellant is introduced and at least one projectile is expelled out of a barrel through the first opening of the firing chamber. 
         [0021]    According to one aspect of the invention, a method is provided for firing and loading a device for shooting projectiles, said device having a firing chamber with first and second openings comprising the steps in any sequence of: 
         [0022]    substantially sealing the second opening of the firing chamber using at least one projectile in the firing chamber and a projectile retention device; 
         [0023]    introducing propellant into the firing chamber wherein at least one projectile is expelled through the first opening; 
         [0024]    relaxing the projectile retention device to allow for additional projectiles to be loaded into the firing chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    These and other aspects, features and advantages of which the invention is capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which: 
           [0026]      FIG. 1  illustrates a known barrel assembly; 
           [0027]      FIG. 2  illustrates a barrel assembly according to one embodiment of the invention; 
           [0028]      FIG. 3  illustrates a barrel assembly according to one embodiment of the invention; 
           [0029]      FIG. 4  illustrates a barrel assembly according to one embodiment of the invention; 
           [0030]      FIG. 5  illustrates a barrel assembly according to one embodiment of the invention; 
           [0031]      FIGS. 6(   a )- 6 ( d ) illustrate a firing sequence according to one embodiment of the invention; and 
           [0032]      FIG. 7  illustrates a multi-barrel assembly according to one embodiment of the invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0033]    The following description focuses on an embodiment of the present invention applicable to a weapon and in particular to a gun. However, it will be appreciated that the invention is not limited to this application but may be applied to any projectile acceleration device, including but not limited to weapons, weapon arrays, firearms, pneumatic guns, BB guns, paintball guns etc. 
         [0034]      FIG. 2  illustrates a gun  200  using a barrel assembly  201  according to one embodiment of the invention. In addition to the barrel assembly  201 , the gun also comprises, among other features, a trigger system  202 , a handle  203 , an electronic control circuit  204 , a battery  205 , a supply of propellant  206  and a propellant injection device  207 . The trigger system  202  may be any type of mechanical or electrical trigger and the invention is not limited thereto. The supply of propellant is connected to the propellant injection device  207 . The supply of propellant may be in a compressed gas cylinder normally containing CO 2 , NO 2 , or air, although other gases may also be used. In addition ignitable propellants can also be used. The propellant injection device  207 , for example, but not limited to, an air solenoid valve, a spring piston sear valve, a solenoid/sear valve combination or a propellant injector with an ignition spark device, is controlled by the control circuit  204 . 
         [0035]    Briefly, in the spring piston sear valve design, dual pistons are stacked on top of each other in two barrels with a interconnecting slot. The pistons are physically linked by a pin in that slot. As the two pistons are trigger released, they spring forward. The top piston chambers a projectile that is gravity fed from an opening on the side. The bottom piston slams into a spring sear valve opening it for a brief moment. This allows a bolus of air to escape which expels the projectile and pushes both pistons back to the firing position. Also, a solenoid valve/sear combination is often used. The solenoid valve air moves the pistons and the sear bolus accelerates the projectile. 
         [0036]    The control circuit  204  also controls how much propellant the propellant injection device  207  injects into the firing chamber so as to vary the force at which the projectile is expelled from the firing chamber. The user of the gun may vary the amount of propellant by, for example, turning a dial on the handle  203  or by inputting the command into the control circuit  204 . 
         [0037]    The barrel assembly  201  comprises, among other features, a firing chamber  208  with a first opening  209  and a second opening  210 , a projectile retention device  211 , a projectile retention device  212 , a storage chamber  213  and a propellant inlet  214  as will be explained in more detail below. 
         [0038]    The operation of the barrel assembly will now be described with reference to  FIGS. 3(   a )- 3 ( d ).  FIG. 3(   a ) illustrates the firing chamber  208  being loaded with two projectiles  215 ,  216 . It will be understood by those skilled in the art that any number of projectiles can be loaded into the firing chamber  208 . The size of the firing chamber  208  can vary and the position of the first and second projectile retention devices  211 ,  212  can also vary to accommodate the desired number of projectiles in the firing chamber  208 . In addition, any number of projectiles in the firing chamber can be fired at the same time except for the last projectile in the firing chamber for the reasons described below. 
         [0039]    The projectiles are first loaded into a storage magazine  213  through a breech. The projectiles are physically biased towards the firing chamber  208  by either gravity and/or mechanical pressure created by axial or rotational spring tension, but the invention is not limited thereto. As illustrated in  FIG. 3 , the projectiles are loaded into a cylinder magazine which has a spring  226  at the end opposite the opening to the firing chamber which biases the projectiles toward the firing chamber. Alternatively, the projectiles may be held in a helical support  228  as illustrated in  FIG. 4 . As the spiral twists under spring tension, the helical support  228  rotates feeding the projectiles forward toward the firing chamber. In addition, the projectiles may be baised towards the firing chamber  208  by gravity as illustrated in  FIG. 5 . In this embodiment, the projectiles are stored in a magazine or hopper which is located above the gun barrel. The projectiles are pulled by gravity down the sloping feed tube  230  as each projectile is moved into the firing chamber. As mentioned above, the design of the storage magazine and the manner in which the projectiles are biased toward the firing chamber is not limited to the illustrative examples described above. 
         [0040]    The projectiles are pushed into the firing chamber  208  until the front projectile rests against the projectile retention device  211 . The projectile retention device  211  may have various forms and the invention is not limited to the following examples. One or more spring loaded or biased pins or flexible pieces of plastic/rubber/metal, for example flanges, may protrude into the bore of the barrel to prevent the front projectile  215  from passing through the first opening  209  of the firing chamber  208  until the gun is fired. Alternatively, a flexible membrane like a rubber washer with a diameter slightly less than the diameter of the bore may be used as the projectile retention device  211 . The flexible membrane can have any type of surface such as smooth, ribbed, etc. While the projectile retention device  211  may have many forms, the retention device must be both resistant to the magazine pressure while compliant to the pressure caused by the injection/ignition of the propellant. 
         [0041]    While the firing chamber is being loaded, the projectile retention device  212 , according to one embodiment of the invention, is in a deflated/dilated condition to allow the projectiles in the storage magazine to be loaded into the firing chamber. According to one embodiment of the invention, the retention device  212  is comprised of a flexible membrane that is either attached radially in the bore of the barrel at the second opening  210  of the firing chamber  208  or is a part of the barrel wall at the second opening  210  of the firing chamber  208 , e.g. where at least a section of the barrel in the firing chamber is flexible and can act as the retention device. The retention device  212  may have many forms, for example a flexible or inflatable membrane, one or more flanges, etc., and the invention is not limited to the described examples. In a first embodiment of the invention, the retention device  212  is a flexible and/or inflatable membrane that takes on substantially the shape of a torus when inflated. In the deflated state, the membrane no longer blocks the second opening and the projectiles can be loaded into the firing chamber  208  as illustrated in  FIG. 6(   a ). When the retention device  212  is inflated, as illustrated in  FIG. 6(   b ), the retention device  212  prevents projectiles from moving through the opening  210 . Furthermore, the last projectile  216  in the firing chamber and the retention device  212  substantially seals the second opening  210  of the firing chamber  208  so as to prevent the injected propellant from seeping through the second opening  210  during firing. 
         [0042]    Alternatively, the retention device  212  may naturally be in a constricted state so as to block the second opening  210  with or without the help of the projectile  216 . In this embodiment, a negative pressure or mechanical/electrical device  220  dilates the retention device  212  from its constricted state to allow for the projectiles to be loaded into the firing chamber. Once the negative pressure or mechanical/electrical device is removed or turned off, then the membrane memory/elasticity of the retention device  212  will return the retention device  212  to the constricted state. 
         [0043]    The opening and closing of the retention device  212  may be controlled by the control circuit  204 . It will be understood that the retention device  212  can be returned to the inflated/constricted state either automatically after the loading sequence is completed or after the firing sequence has began and the invention is not limited thereto. 
         [0044]    As illustrated in  FIG. 6(   c ), in response to the trigger being pulled, the control unit  204  directs the propellant injection system to inject propellant into the firing chamber through the inlet  214 . According to one embodiment of the invention, the propellant enters the firing chamber  208  through an inlet  214 . The inlet is located in front of the last projectile  216  in the firing chamber. When the propellant enters and/or is ignited, the pressure from the propellant forces the projectile  216  against the projectile retention device  212  which helps to substantially seal the second opening of the firing chamber. Once the pressure from the propellant becomes so great, the projectile  215  overcomes the resistance of the projectile retention device  211 , and the projectile  215  is expelled out of the firing chamber  208  and through the barrel of the gun as illustrated in  FIG. 6(   d ). The retention device  212  then deflates/dilates and the next projectile in the storage magazine is introduced into the firing chamber moving the projectile  216  up against the retention device  211  and the gun is ready to be fired again. Furthermore, the gun may also comprise means for detecting whether the gun is in a proper firing condition. These means may include mechanical sensing means for detecting projectile pressure on a retaining device,e.g. projectile retention device  211 , or means for detecting occlusion of a light path (not shown). 
         [0045]    According to one embodiment of the invention, the gas or air expelled from the retention device  212  during deflation can be directed through an inlet  217  in the storage magazine  213  to help facilitate the loading of the next projectile into the firing chamber. It will be understood that the inlet can be positioned anywhere in the storage magazine. 
         [0046]    As illustrated in  FIG. 7 , the invention can also be applied to weapons which have multiple barrels. While  FIG. 7  illustrates  2  barrels, the invention can be applied to any number of barrels. According to the invention, each barrel has the same features as a single barrel assembly namely, its own firing chamber  208 ,  208 ′, retention device  211 ,  211 ′, retention device  212 ,  212 ′, inlet  214 ,  214 ′ and projectiles  215 ,  216 ,  215 ′,  216 ′. The multi-barrel weapon may have multiple propellant reservoirs, propellant injection devices, and control circuits and electrical supply, but the invention is not limited thereto. Each barrel assembly operates in the same manner described above with reference to  FIGS. 6(   a )- 6 ( d ). 
         [0047]    The invention can be implemented in any suitable form including hardware, software, firmware or any combination of these. The elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the invention may be implemented in a single unit, or may be physically and functionally distributed between different units and processors. 
         [0048]    Although the present invention has been described above with reference to (a) specific embodiment(s), it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims and, other embodiments than the specific above are equally possible within the scope of these appended claims. 
         [0049]    In the claims, the term “comprises/comprising” does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms “a”, “an”, “first”, “second” etc do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.