Patent Abstract:
A paintball marker has an inline cylinder that includes a gas governor that reduces gas flow from a compressed gas source to a valve area when the bolt is in a firing position; this increases efficiency in the marker because only the required air is used to fire the paintball. This bolt operates independent of the valve pin, which increases cycle speed and enables the governor to open and close at an optimum time in the firing cycle. Further, when the bolt/piston is recocking, the gap between the valve pin and governor valve pin enables low pressure gas driving the piston to start pressurizing the cylinder and driving the piston rearwards without resistance from the high pressure gas. The marker also allows a user to remove the inline cylinder without tools, and provides a convenient carrying handle for holding the paintball marker, which is commonly called a “snatch grip.”

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/370,674, filed Feb. 10, 2012, issuing as U.S. Pat. No. 8,505,525 on Aug. 13, 2013, which is a continuation of U.S. patent application Ser. No. 12/271,402, filed Nov. 14, 2008, which issued as U.S. Pat. No. 8,113,189 on Feb. 14, 2012, which is a continuation of U.S. patent application Ser. No. 11/352,639, filed Feb. 13, 2006, which issued as U.S. Pat. No. 7,451,755 on Nov. 18, 2008, which is a continuation-in-part of U.S. patent application Ser. No. 11/183,548, filed Jul. 18, 2005, now abandoned, which claims the benefit of U.S. Provisional Patent Application Nos. 60/588,912, filed Jul. 16, 2004 and 60/654,262, filed Feb. 18, 2005 respectively, and also claims the benefit of U.S. Provisional Patent Application Nos. 60/652,157, filed Feb. 11, 2005 and 60/654,120, filed Feb. 18, 2005 respectively, all of which are incorporated by reference as if fully set forth herein. 
    
    
     BACKGROUND 
     This invention relates generally to the construction of compressed gas guns and more particularly to the guns designed to propel a liquid containing frangible projectile, otherwise known as a “paintball.” As used herein, the term “compressed gas” refers to any mean known in the art for providing a fluid for firing a projectile from a compressed gas gun, such as a CO2 tank, a nitrous tank, or any other means supplying gas under pressure. Older existing compressed gas guns generally use a mechanical sear interface to link the trigger mechanism to the hammer or firing pin mechanism. In these guns, a trigger pull depresses the sear mechanism which allows the hammer, under spring or pneumatic pressure, to be driven forward and actuate a valve that releases compressed gas through a port in the bolt, which propels a projectile from the barrel. 
     This design, however, has many problems, including increased maintenance, damage after repeated cycles, and a higher amount of force is required to drive the hammer mechanism backwards to be seated on the sear. Also, because the sear and resulting hammer must be made of extremely hard materials, the gun is heavy. Such weight is a disadvantage in paintball, where a player&#39;s agility works to his advantage. 
     To overcome the problems of a mechanical sear, other solutions have been developed. One solution uses a pneumatic cylinder, which uses spring or pneumatic pressure on alternating sides of a piston to first hold a hammer in the rearward position and then drive it forward to actuate a valve holding the compressed gas that is used to fire the projectile. Although the use of a pneumatic cylinder has its advantages, it requires the use of a stacked bore, where the pneumatic cylinder in the lower bore and is linked to the bolt in the upper bore through a mechanical linkage. It also requires increased gas use, as an independent pneumatic circuit must be used to move the piston backwards and forwards. A further disadvantage is that adjusting this pneumatic circuit can be difficult, because the same pressure of gas is used on both sides of the piston and there is no compensation for adjusting the amount of recock gas, used to drive it backwards, and the amount of velocity gas, which is the amount of force used to drive it forward and strike the valve. This results in erratic velocities, inconsistencies, and shoot-down. In addition, this technology often results in slower cycling times, as three independent operations must take place. First, the piston must be cocked. Second, the piston must be driven forward. Third, a valve is opened to allow compressed gas to enter a port in the bolt and fire a projectile. Clearly, the above design leaves room for improvement. 
     Single-bore designs have been developed which place the cylinder and piston assembly in the top bore, usually behind the bolt. This reduces the height of the compressed gas gun, but still requires that a separate circuit of gas be used to drive the piston in alternating directions, which then actuates a valve to release compressed gas, which drives the bolt forward to launch a paintball. These are generally known as spool valve designs. See, for instance, U.S. Pat. Nos. 5,613,483 and 5,494,024. 
     Existing spool valve designs have drawbacks as well. Coordinating the movements of the two separate pistons to work in conjunction with one another requires very precise gas pressures, port orifices, and timing in order to make the gun fire a projectile. In the rugged conditions of compressed gas gun use, these precise parameters are often not possible. In addition, adjusting the velocity of a compressed gas gun becomes very difficult, because varying the gas pressure that launches a paintball in turn varies the pressure in the pneumatic cylinder, which causes erratic cycling. 
     What is needed is a compressed gas gun design that eliminates the need for a separate cylinder and piston assembly and uses a pneumatic sear instead of a pneumatic double-acting cylinder to hold the firing mechanism in place prior to firing a projectile. This allows the gun to be very lightweight and compact, and simplifies adjusting the recock gas used to cock the bolt and the gas used to fire the projectile. A further need exists for an easily removable inline cylinder that can be removed, preferably without using tools, so that the marker can be field-stripped and maintained. 
     SUMMARY 
     The current invention addresses these needs. The main advantage is that the inventive inline cylinder includes a gas governor that reduces gas flow from a compressed gas source to a valve area when the bolt is in a firing position; this increases efficiency in the marker because only the required air is used to fire the paintball. This particular design operates independent of the valve pin, which increases cycle speed and enables the governor to open and close at the optimum time in the firing cycle. Further, when the bolt/piston is recocking, the gap between the valve pin and governor valve pin enables low pressure gas driving the piston to start pressurizing the cylinder and driving the piston rearwards without resistance from the high pressure gas. 
     It allows a user to remove the inline cylinder without the use of tools, and gives the user a convenient carrying handle for holding the paintball marker, which is commonly called a “snatch grip.” 
     Further, the invention uses a safety mechanism that prevents the inline from being removed while the marker is pressurized without the safety, such removal would result in the inline cylinder being driven backwards out of the marker. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects of the invention will be more readily apparent upon reading the following description of embodiments of the invention and upon reference to the accompanying drawings wherein: 
         FIG. 1  is a side view of a compressed gas gun utilizing a variable pneumatic sear in the firing position. 
         FIG. 2  is a side view of a compressed gas gun utilizing a variable pneumatic sear in the loading position. 
         FIG. 3  is an expanded view of the variable pneumatic sear in the loading position. 
         FIG. 4  is an expanded view of the variable pneumatic sear in the launching position. 
         FIG. 5  is an expanded isometric view of the switches located within the recess. 
         FIGS. 6 and 6A  are cross-sections of an alternate embodiment showing an inline cylinder in the loading position. 
         FIGS. 7 and 7A  are cross-sections of an alternate embodiment showing an inline cylinder in the firing position. 
         FIG. 8  is a cross section of the rear end of the marker having the inline cylinder of  FIG. 6 . 
         FIG. 9  is a cross section of the rear end of the marker having the inline cylinder of  FIG. 6 . 
         FIG. 10  is a cross section of the rear end of the marker having the inline cylinder of  FIG. 6 . 
         FIG. 11  is an elevation of the rear end of the marker having the inline cylinder of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1-5  illustrate of a compressed gas gun incorporating a pneumatic sear. Referring to  FIGS. 1 and 2 , a paintball gun generally comprises a main body  3 , a grip portion  45 , a trigger  24 , a feed tube  6 , and a barrel  10 . These components are generally constructed out of metal, plastic, or a suitable substance that provides the desired rigidity of these components. Main body  3  generally is connected to a supply of projectiles by feed tube  6  as understood by those skilled in the art. Main body  3  is also connected to grip portion  45 , which houses the trigger  24 , battery  64  and circuit board  63 . The trigger  24  is operated by manual depression, which actuates micro-switch  86  directly behind trigger  24  to send an electrical signal to circuit board  63  to initiate the firing or launching sequence. Barrel  10  is also connected to body  3 , preferably directly in front of feed tube  6 , to allow a projectile to be fired from the gun. 
     Hereinafter, the term forward shall indicate being towards the direction of the barrel  10  and rearward shall indicate the direction away from the barrel  10  and towards the rear of main body  3 . Preferably forward of the grip portion  45 , and also attached to main body  3 , the regulator mount  2  houses both the low-pressure regulator  21  and the high-pressure regulator  50 . Compressed gas is fed from preferably a compressed gas tank into the input port  49  on high-pressure regulator  50  to be directed to tube  7  to launch a projectile and to be directed to low pressure regulator  21  to cock the bolt tip  38  for loading. Both regulators  21 ,  50  are constructed from principles generally known to those skilled in the art, and have adjustable means for regulating compressed gas pressure. 
     Referring more particularly to  FIGS. 3 and 4 , housed within main body  3  is the firing mechanism of the gun. The firing mechanism preferably comprises a bolt tip  38 , which is preferably constructed out of delrin or metal and is connected to piston  32 , housed in cylinder body  31 . Piston  32  is also constructed out of delrin or metal, and is connected to valve pin  33 , housed on the interior of piston  32 . In the loading position, valve pin  33  is forced rearward by compressed gas at a low pressure (described in more detail below) and seal  70  (located on a rearward portion  33   a  of the valve pin  33 ) is pushed against the lip  75  of valve housing tip  35 , holding high-pressure compressed gas A on the rearward face  33   b  of valve pin  33  and preventing the flow or high pressure gas through bolt tip  38 . All seals, including o-ring  70  are constructed out of urethane, plastic, rubber, silicone, BUNA, TEFLON, or any other substance that effectively prevents gas leakage beyond the surface of the seal. Valve housing tip  35  is integrally connected to valve housing  34 , which prevents leakage of high-pressure compressed gas around the valve housing  34 . Seals  102  also prevent leakage of high-pressure gas and are placed at connecting section of the various components. Cylinder  31  surrounds valve housing  34  and provides sealed housing for piston  32 , which contains a first surface  72  for low pressure gas B to flow into to drive piston  32  rearward and seal valve pin  33  against tip  35 . Valve housing  34  preferably contains an interior chamber  36  for storing compressed gas to be used to fire a projectile from the gun. 
     The variable pneumatic sear  29  of the compressed gas gun of the present invention preferably consists of a control valve  30 , a piston  32 , residing in preferably sealed cylinder housing  31  as shown in  FIG. 1 . Control valve  30  directs low pressure compressed gas from low pressure regulator  21  through manifold  41  to the cylinder housing  31 , allowing gas to contact first surface of piston  32 , driving the piston  32  rearward to seat the valve pin  33  when de-actuated, which is considered the loading position. The low pressure compressed gas is able to drive the piston  32  rearward against high-pressure gas pressure on valve pin  33  because the surface area of first surface  72  of piston  32  is larger than that of the surface of valve pin  33 . Control valve  30  preferably consists of a normally open three-way valve. When actuated, a normally open valve will close its primary port and exhaust gas from the primary port, thereby releasing pressure from the first surface of piston  32 , through a port  42  drilled into manifold  41 . This allows high pressure compressed gas, pushing against the smaller surface area of valve pin  33 , to drive valve pin  33  forward and break the seal by o-ring  70  to release the stored gas from valve housing  34 . Compressed gas then flows around valve pin  33 , through ports  32   a  in piston  32 , and out through bolt tip  38  to launch a projectile from the barrel  10 . 
     Control valve  30  is preferably controlled by an electrical signal sent from circuit board  63 . The electronic control circuit consists of on/off switch  87 , power source  64 , circuit board  63 , and micro-switch  86 . When the gun is turned on by on/off switch  87 , the electronic control circuit is enabled. For convenience, the on/off switch  87  (and an optional additional switches, such as that for adjacent anti-chop eye that prevents the bolt&#39;s advance when a paintball  100  is not seated within the breech) is located on the rear of the marker, within a recess  88  shielded on its sides by protective walls  89 . This location protects the switch  87  from inadvertent activation during play. The switch  87  is preferably illuminated by LEDs. 
     When actuating switch  86  by manually depressing trigger  24 , an electrical signal is sent by circuit board  63  to the control valve  30  to actuate and close the primary port, thereby releasing valve pin  33  and launching a projectile. Once the momentary pulse to the control valve  30  is stopped by circuit board  63 , the electronic circuit is reset to wait for another signal from switch  86  and the gun will load its next projectile. In this manner, the electrical control circuit controls a firing operation of the compressed gas gun. 
     A description of the gun&#39;s operation is now illustrated. The function of the pneumatic sear is best illustrated with reference to  FIGS. 3 and 4 , which depict the movements of piston  32  more clearly. Compressed gas enters the high-pressure regulator  50  through the input port  49 . The high-pressure regulator is generally known in the art and regulates the compressed gas to about 200-300 p.s.i. These parameters may be changed and adjusted using adjustment screw  51 , which is externally accessible to a user for adjustment of the gas pressure in the high-pressure regulator. This high-pressure gas is used to actuate the firing valve and launch a projectile from the barrel  10  of the compressed gas gun. Upon passing through high-pressure regulator  50 , compressed gas is fed both through gas transport tube  7  to the valve chamber  36  via manifold  8 , and through port  5  to the low pressure regulator  21 . Low-pressure regulator  21  is also generally known in the art. Compressed gas is regulated down to approximately between 50-125 p.s.i. by the low-pressure regulator, and is also adjusted by an externally accessible adjustment screw/cap  28 , which is preferably externally manually adjustable for easy and quick adjustment. Compressed gas then passes through port  25  into manifold  41 , where electro-pneumatic valve  30  directs it into cylinder housing  31  through low pressure passages  74  and low pressure gas pushes against first surface  72  on piston  32 , driving it rearwards and seating seal  70  against valve housing tip  35 . Note that piston&#39;s  32  movement in the rearward direction is limited by contact between the second surface  76  and a stop  34   a  on the valve housing  34 . 
     This allows bolt tip  38  to clear the breech area of the body  3 , in which stage a projectile  100  moves from the feed tube  6  and rests directly in front of bolt tip  38 . The projectile is now chambered and prepared for firing from the breech. The high-pressure compressed gas, which has passed into the valve chamber  36  via high pressure passage  37 , is now pushing against valve pin  33  on the rear of piston  32 . The seal created by o-ring  70  on valve pin  33  is not broken because the force of the low-pressure gas on the first side of cylinder  31  is sufficient to hold the valve pin  33  rearward. 
     When trigger  24  is depressed, electro-pneumatic valve  30  is actuated (preferably using a solenoid housed within the manifold  41 , shutting off the flow of low-pressure gas to housing  31  and venting the housing  31  via manifold  41 . This allows the higher pressure gas, which is already pushing against valve tip  33  from the rear, to drive valve tip  33  forward to the firing position and break the seal  70  against the housing  35 . Bolt tip  38 , which is connected to piston  32 , pushes a projectile forward in the breech and seals the feed tube  6  from compressed gas during the first stage of launch because the valve pin  33  is still passing through valve housing tip  35  during this stage. This prevents gas leakage up the tube  6  and positions the projectile for accurate launch. Once the valve pin  33  clears the housing tip  35 , a flow passage D is opened, and the higher pressure gas flows through ports  32   a ,  38   a  drilled through the interior of piston  32  and bolt tip  38  and propels the paintball from barrel  10 . Note that the piston&#39;s  32  movement in the forward direction is limited by contact between the first surface  72  and a shoulder  73  within the cylinder  31 . 
     The signal sent to electro-pneumatic valve  30  is a momentary pulse, so when the pulse ceases, the valve  30  is de-actuated. This allows low-pressure gas to enter cylinder housing  31  and drive valve piston  32  rearwards against the force exerted by high-pressure gas to the seated position and allow loading of the next projectile. 
     Since piston  32  has a larger surface area on its outside diameter than the surface area on the valve pin  33 , low-pressure gas is able to hold high-pressure gas within the valve chamber  36  during the loading cycle of the gun. This is more advantageous than a design where a separate piston is used to actuate a separate valve, because the step of actuating and de-actuating the piston is removed from the launch cycle. 
     In addition, the pressures of the low pressure gas and high pressure gas may be varied according to user preference, thereby allowing for many variable pneumatic configurations of the gun and reducing problems with erratic cycling caused by using the same gas to control both the recock and launch functions of the gun. Because the mechanical sear is eliminated, the gun is also extremely lightweight and recoil is significantly reduced. The gun is also significantly faster than existing designs because the independent piston operation is eliminated. 
     In an alternate embodiment, the compressed gas gun can operate at one operating pressure instead of having a high-pressure velocity circuit and a low-pressure recock circuit. This is easily accomplished by adjusting the ratio of the surface sizes of the first surface  72  and the valve pin  33 . In this manner, the size of the gun is reduced even more because low-pressure regulator  21  is no longer needed. 
       FIGS. 6-11  show an alternate embodiment of the paintball marker that shares many elements in common with the marker in  FIGS. 1-5 —the biggest difference between the embodiments being the inline cylinder  314 . Common elements between the inline cylinder  314  in  FIGS. 6-11  and the cylinder  14  in  FIGS. 1-5  have similar names and numbers between the embodiments and it should be appreciated that low pressure inlet passages  374  and high pressure inlet passages  341  correspond to the low and high pressure inlet passages  74 ,  37 . 
     The marker of  FIGS. 6-11  comprises a main body  3 , a grip portion  45 , a trigger  24 , a feed tube  6 , and a barrel  10 . The main body  3  comprises a bore  300  therethrough that slidably contains an inline cylinder  314 , which houses the paintball marker&#39;s firing mechanism. 
     When a user removes the mechanical linkage  400  from within the bores  302 ,  402  as shown in  FIGS. 10 and 11 , the user can slide the inline cylinder  314  from within the bore  300 . The mechanical linkage comprises two joined portions: the handle  404  and the locking pin  406 . The handle serves two purposes. First, pressing the handle  404  downwards in relation to the marker body, pulls the locking pin  406  from the bores  302 ,  402 , which allows removal of the inline cylinder  314 . This removal can be done without the use of any specialty tools. Second, the convex area  408  serves as a “snatch grip,” which is well-known in the filed of paintball markers, and allows a marker to be safely carried during down times in a game—its specific purpose is that it allows transport of a marker without placing a user&#39;s hands and fingers near the trigger  24  where they might accidentally discharge the marker. 
     The locking pin  406  extends through the bores  302 ,  402  to lock the inline cylinder  314  within the marker bore  300 , and prevent motion between the inline cylinder  314  and the marker. As best seen in  FIGS. 8 and 9 , a spring  306  biases a button  304  rearwards into the groove  410  to hold the mechanical linkage  400  in place. Further, when high pressure compressed gas fills the firing chamber  308 , the compressed gas fills the chamber around the button  304 , which is sealed by seal  304   a , and drives the button  304  rearwards into the groove  410  with such force that a user cannot remove the mechanical linkage from the marker. This prevents the compressed gas from driving the inline cylinder  314  from the marker when it is pressurized. 
     It should be appreciated, from  FIGS. 6, 6A, 7, and 7A  particularly, that seals  350 ,  352 ,  354 , and  356  prevent leakage from the inline cylinder  314  through the bore  300 . 
     The operation of the inline cylinder  314  during the firing cycle will now be described. The control valve  30  directs low pressure compressed gas from low pressure regulator  21  through manifold  41  through the low pressure passages  374  to bolt chamber  331  allowing gas to contact first surface  332   a  of piston  332 , driving the piston  332  rearward. Rearward movement of the piston  332  moves the valve pin  333  rearwards, which results in a seal between the seal  370  and the valve housing  360 . This is considered the loading position because the piston&#39;s tip  338  clears the breech  101  and allows a paintball  100  to drop into the breech  101 . (This loading position corresponds to the bolt position in  FIG. 2 .) 
     Meanwhile, high pressure gas from the high pressure regulator flows through high pressure passage  341 , then through cylinder channels  339 , through governor channels  382 , into the governor chamber  380 , through firing chamber channels  384 , and into the firing chamber  308 . The low pressure compressed gas drives the piston  332  rearward, overcoming high-pressure gas pressure on valve pin  333  because the surface area of first surface  332   a  of piston  332  is larger than that of the surface area  333   a  of valve pin  333 . In this loading position shown in  FIGS. 6, 8, 9, and 10 , the air flow into the firing chamber  308  is indicated by A. 
     As with the embodiment of  FIGS. 1-5 , the control valve  330  preferably is a normally open three-way valve. When actuated in response to a trigger pull, the normally open valve will close its primary port and exhaust low pressure gas from the bolt chamber  331  through the low pressure passage  374 , releasing low pressure gas from the first surface  332   a  of piston  332 . This allows high pressure compressed gas in the firing chamber  308 , pushing against the smaller surface area  333   a  of valve pin  333 , to drive the pin  333  and bolt  332  forwards because of contact between the pin  333  and bolt  332 . This moves the o-ring  370  forwards of valve housing ports  335 , releasing the high pressure gas in the firing chamber  308 . The high pressure gas flows into the valve housing  360  around valve pin  333 , through ports  335 , into a piston passage  337  in piston  332 , and out through bolt tip channels  338   a  in bolt tip  338  to launch a projectile  100  from the barrel  10 . In this firing position shown in  FIGS. 7 and 7A , the air flow to fire the paintball is indicated by A. 
     The function of the inline cylinder  314  and gas governor  380  can best be appreciated in  FIGS. 6, 6A, 7, and 7A . In  FIGS. 6 and 6A , in the loading position, high pressure gas in the gas governor chamber  385  forces the gas governor pin  386  rearward, overcoming a forward bias of the gas governor pin from spring  306 . Upon firing, the forward movement of the valve pin  333  combined with the exhaust of the high pressure gas from the barrel  10 , allows the spring  306  to drive the gas governor pin  386  forwards to its maximum forward position shown in  FIGS. 7 and 7A . In this forward position, the flow of high pressure gas into the firing chamber  308  is cut off because the gas governor pin  386  blocks gas governor ports  382 . 
     This high pressure cutoff results in a faster loading cycle, which begins when the normally open valve low pressure valve reopens and low pressure gas acts on the forward surface  332   a  of bolt  332 . The cycle is faster because it does not have to overcome high pressure gas in the firing chamber  308  as the low pressure gas drives bolt  332  rearward, since there is no or little high pressure gas in the firing chamber  308 . As the low pressure gas drives the bolt  332  rearward, the valve  333  engages the gas governor pin  386  and drives it backwards to its position in  FIGS. 6 and 6A . 
     The length of the governor pin  386  can also be manipulated to change the timing of the opening and closing of the governor without affecting the firing cycle. 
     While the present invention is described as a variable pneumatic sear for a paintball gun, it will be readily apparent that the teachings of the present invention can also be applied to other fields of invention, including pneumatically operated projectile launching devices of other types. In addition, the gun may be modified to incorporate a mechanical or pneumatic control circuit instead of an electronic control circuit, for instance a pulse valve or manually operated valve, or any other means of actuating the pneumatic sear. 
     It will be thus seen that the objects set forth above, and those made apparent from the preceding description, are attained. It will also be apparent to those skilled in the art that changes may be made to the construction of the invention without departing from the spirit of it. It is intended, therefore, that the description and drawings be interpreted as illustrative and that the following claims are to be interpreted in keeping with the spirit of the invention, rather than the specific details. set forth. 
     It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described and all statements of the scope of the invention that, as a matter of language, might be said to fall therebetween.

Technology Classification (CPC): 5