Patent Publication Number: US-2005115549-A1

Title: Combination fill nipple and on/off valve for a paintball gun

Description:
RELATED APPLICATION DATA  
      This application claims priority from U.S. Provisional Patent Application Ser. No. 60/498,917, filed Aug. 28, 2003, which hereby incorporates by reference. 
    
    
     BACKGROUND OF THE INVENTION  
      This invention relates generally to paintball guns. More specifically, this invention relates to a paintball gun on/off valve and fill nipple for selectively controlling a supply of gas from a compressed gas source to a compressed gas storage tank and from a compressed gas storage tank to a paintball gun.  
      A reliable on/off valve for selectively supplying a flow of compressed gas to a paintball gun from a compressed gas tank is shown and described in U.S. Pat. No. 6,260,821 B1 (the contents of which are incorporated herein by reference in their entirety), which issued Jul. 17, 2001 to Perry et al., and was assigned to Smart Parts, Inc. In particular, the on/off valve shown and described in Perry et al. overcame reliability problems with preexisting on/off valves, including leakage of the compressed gas.  
       FIG. 1  is a perspective view of a paintball gun  50  having a conventional on/off valve  100 .  FIG. 2  is an enlarged side elevation view of the on/off valve  100  of  FIG. 1 , showing the external attachment between a pressure regulator  55  of a paintball gun  50  and a compressed gas source  60 . The on/off valve  100  of  FIGS. 1 and 2  is typical for paintball guns using compressed air or nitrogen as the compressed gas source  60 .  FIG. 2A  is a side elevation view of an on/off valve  100 A, similar to the valve  100  shown in  FIGS. 1 and 2 . The compressed gas source  60 A, used with the valve  100 A, is a CO 2  source.  FIG. 3  is a bottom right side perspective view of the prior art on/off valve  100 A of  FIG. 2A , shown independent of attachment to external components. The only structural differences between the valve  100  shown in  FIGS. 1 and 2  and the valve  100 A of  FIGS. 2A and 3  are the type of actuator  122  used and the size of the valve.  FIGS. 1 and 2  show a lever-type actuator  122  on a larger valve for use with a compressed air or nitrogen gas source  60 , while  FIG. 3  shows a knob-type actuator  122 A for use with a compressed CO 2  gas source  60 A.  
      The internal configuration of the conventional on/off valves  100 ,  100 A is shown in  FIGS. 4-7 . Specifically,  FIG. 4  is a horizontally cross-sectioned bottom plan view of the prior art on/off valve  10 A, shown in  FIG. 3 .  FIG. 5  is an enlarged, vertically cross-sectioned, partial right side elevation view of the prior art on/off valve  100 A of  FIG. 3 .  FIG. 6  is a front elevation view and a cutaway left side elevation view of a plug  120  for use in the prior art on/off valve  100 A of  FIG. 3 .  FIG. 7  is a horizontally cross-sectioned bottom plan view and a vertically cross-sectioned front elevation view of a valve body  102  for use in the prior art on/off valve  100 A of  FIG. 3 . The general internal configuration of the valve  100  is the same as that for valve  100 A, except with respect to the sizing of the components.  
      Referring to  FIGS. 4-7 , this conventional on/off valve  100 A has a valve body  102  with a gas inlet  110  and a gas outlet  112  extending longitudinally through the body  102 . The valve body  102  also includes a plug cavity  115  that extends laterally through the body  102  between the inlet  110  and the outlet  112  from a right side (top of  FIG. 4 ) to a left side (bottom of  FIG. 4 ) of the body  102 . A plug  120  is positioned within the plug cavity  115 . The plug includes a knob (or other actuator)  122 A that can be rotated  900  to switch the valve  100 A on or off. The actuator  122 A is attached to a plug stem  124  that extends into and through the plug cavity  115 . A flow aperture  125  is provided through the plug stem  124 , and is located at the lateral position of the inlet  110  and the outlet  112 , when the plug stem  124  is properly arranged inside the cavity  115 .  
      Two o-rings  126 ,  126 A extend around the plug stem  124  within grooves  127 ,  127 A on opposite lateral sides of the inlet  110  and outlet  112 . These o-rings  126 ,  126 A provide a seal between the plug stem  124  and the wall of the cavity  115  to prevent the gas from leaking out through the plug ends and to ensure that the gas from the gas inlet  110  travels to the gas outlet  112  when the valve  100 A is open. A third o-ring  128  is provided along the external surface of the plug stem  124  within a circular-shaped groove  129 . The third o-ring  128  is designed to prevent gas from leaking into the outlet  112  and, hence, from flowing to the gun  50 , when the actuator  122 A is in an “off” (closed valve) position. Specifically, when the actuator  122 A is located in an “off” position, the o-ring  128  surrounds an entry port  113  of the outlet  112 , preventing the gas from entering the outlet  112 . It should be noted that the third o-ring  128  only performs its sealing function when the valve is in the “off” position.  
      Referring to  FIGS. 1-7 , the operation of the prior art on/off valves  100 ,  100 A is as follows. When the actuator  122 ,  122 A is located in an “on” (open valve) position, the flow aperture  125  in the plug stem  124  is arranged in communication with both the inlet  110  and the outlet  112  in order to permit the gas to flow from the inlet  110  to the outlet  112 . When the actuator  122 ,  122 A is rotated  900  from the open position into a closed position, the third o-ring  128  slides into place around the entry port  113  of the outlet  112 , and the flow aperture  125  is positioned transverse to an axis running from the inlet  110  to the outlet  112 . This system works fairly well for compressed air and Nitrogen systems which have larger valve sizes.  
      Unfortunately, however, this configuration has several disadvantages when used for CO 2  systems, which generally have smaller valves. In particular, the wall of the plug cavity  115  is very difficult to debur, particularly around the entry port  113  of the outlet  112 . This is because the cavity  115  and port  113  are located inside the valve body  102 . Inevitably, therefore, small, sharp protrusions are left on the wall surface of the cavity  115 . These protrusions tend to cut or slice the o-ring  128  as the plug  120  is rotated from the open to the closed position. Specifically, burs around the entry port  113  of the outlet  112  tend to slice the o-ring  128  as it slides past to reach the closed position. Once the o-ring  128  has been cut, it can no longer provide an adequate sealing function and gas will leak into the outlet  112  even when the valve  100 A is closed.  
      In addition, the o-ring  128  of the valve  100 A is relatively large and pliable, e.g., a 007-70° Urethane (U) or Ethylene Propylene (EP) o-ring. With this o-ring  128 , when CO 2  is used as the compressed gas, the o-ring  128  has a tendency to absorb the CO 2  and expand as a result. Also, because the o-ring  128  is fairly large in proportion to the diameter of the plug  120 , it tends to come out of its groove  129 . Furthermore, pressure from the gas source tends to force the o-ring  128  into contact with the valve body  102 . The expansion forces and gas pressure increase the contact between the o-ring  128  and the body  102 , thereby increasing the likelihood that surface irregularities along the cavity walls (and particularly around the entry port  113  of the outlet  112 ) will destroy the o-ring  128 . When the o-ring  128  is destroyed, the compressed gas begins to leak from the on/off valve  10 A, shortening the life of the gas source. Because of this, the on/off valve  100 A is not sufficiently reliable.  
      The improved on/off valves  200 ,  200 A, and  200 B of Perry et al., which are shown in  FIGS. 8-13 , provided a significant improvement in the art by enabling an on/off valve for a paintball gun with improved reliability. Specifically, in Perry et al., the improved on/off valves have a valve body with a plurality of gas apertures. The gas apertures include a gas inlet configured to receive a gas from a pressurized gas source, and a gas outlet configured to transmit the gas to a paintball gun. An actuator is configured to selectively control a flow of the gas from the gas inlet to the gas outlet. A seal is located inside a port of one or more of the apertures to prevent the gas from leaking.  
      In operation, the valve is switched between an open (“on”) position and a closed (“off”) position by actuation of the actuator. In an open position, the flow of gas is permitted between the gas inlet and the gas outlet. In a closed position, the flow of gas is interrupted. The seal operates to prevent gas from leaking from the port in which it is located. The seal performs its sealing function when the valve is in its open position as well as when it is in its closed position.  
      More specifically,  FIG. 8  includes a horizontally cross-sectioned bottom plan view of an on/off switch  200  of Perry et al.  FIG. 9  is a vertically cross-sectioned, enlarged right side elevation view of a section of the on/off valve  200  of  FIG. 8 .  FIG. 10  includes an enlarged front elevation view and a cutaway left side elevation view of a plug  220  for use in the on/off valve  200  of  FIG. 8 . Finally,  FIG. 11  includes a horizontally cross-sectioned bottom plan view and a vertically cross-sectioned front elevation view of a valve body  202  for use in the on/off valve  200  of  FIG. 8 .  
      The improved on/off valve  200  of Perry et al. has a valve body  202  with gas apertures including a gas inlet  210  and a gas outlet  212 , each extending longitudinally through the body  202 . The valve body  202  further includes a plug cavity  215 , extending laterally through the body  202  between the inlet  210  and the outlet  212 . A plug  220  is positioned within the plug cavity  215 . An actuator (such as a knob, lever, or other actuator)  222  is provided on an external portion of the plug  220 . Here, the actuator  222  is a knob that is physically attached to a plug stem  224 . The plug stem  224  extends into and through the plug cavity  215  from the right side to the left side of the valve body  202 . A flow aperture  225  is provided through the plug stem  224  at the lateral position of the inlet  210  and the outlet  212 . The actuator  222  can be rotated 90° to turn the valve  200  on or off.  
      Two o-rings  226 ,  226 A extend around the plug stem  224  within grooves  227 ,  227 A on opposite lateral sides of the inlet  210  and outlet  212 . The o-rings  226 ,  226 A prevent the gas from leaking out through the plug ends and ensure that the gas from the gas inlet  210  travels to the gas outlet  212  when the valve  200  is open. They also provide redundancy and dust protection. When the actuator  222  is located in an “on” position, the flow aperture  225  is arranged in communication with both the inlet  210  and the outlet  212  in order to permit a flow of the gas from the inlet  210  to the outlet  212 .  
      A body o-ring  230  is provided within the valve body  202 , rather than along the external surface of plug stem  224 . Specifically, the body o-ring  230  is located inside either an exit port  211  of the gas inlet  210  or in an entry port  213  of the gas outlet  212 . In this case, the body o-ring  230  is located in the exit port  211  of the inlet  210 . The body o-ring  230  provides a seal between the valve body  202  and the plug stem  224 , and prevents gas from leaking out of the inlet  210 . Because the o-ring surrounds the inlet  210  of the valve body, it helps prevent gas leakage regardless of the position of the actuator  222 . It performs its sealing function when the actuator is in the “on” position (open valve) as well as when it is in the “off” position (closed valve).  
      This configuration prevents the body o-ring  230  from moving relative to the valve body  202  and thereby substantially eliminates the risk of the body o-ring  230  being cut or damaged by burs in the body  202 . This is particularly advantageous because it is easier to machine the plug stem  224  to remove burs than to remove burs from the surface of the plug cavity  215 . Accordingly, movement of the finely-machined plug stem  224  in relation to the body o-ring  230  is much less likely to damage the o-ring  230  than the movement of the plug o-ring  128  in relation to the body  102 . The body o-ring  230  will therefore have a significantly longer life than the prior art plug o-ring  128  and provide a more reliable on/off valve  200 .  
      In operation, the valve  200  is switched between an open (“on”) position and a closed (“off”) position through 90° rotation of the plug  224  via the actuator  220 . In an open position, the flow aperture  225  is arranged in communication with the inlet  210  and permits a flow of gas from the inlet  210  to the outlet  220 . In a closed position, the communication between the flow aperture  225  and the inlet  220  is severed because the flow aperture  225  is then positioned transverse to the longitudinal axes of the inlet  210  and outlet  220 . The body o-ring  230  provides a seal between the valve body  202  and the plug  220  when the valve is in either the open or the closed position. In the open position, the seal ensures the gas will travel through the flow aperture  225 . In a closed position, the seal retains the gas within the inlet  210 .  
      Gas pressure from the pressurized gas source  60  enhances the sealing properties of the body o-ring  230  by encouraging the o-ring  230  into physical communication with the plug  220 . Pressure arrows  232  in  FIG. 9  illustrate how the gas pressure helps maintain the body o-ring  230  in a sealing position. As gas travels to the exit port  211  of the inlet  210  it comes into contact with the body o-ring  230  and pushes it outward toward the plug stem  224 .  
      Also, because the o-ring  230  is located in the valve body  202 , rather than along the surface of the plug stem  224 , rotation of the plug  220  does not substantially move the o-ring  230  in relation to the valve body  202 . Accordingly, the only movement of consequence for the body o-ring  230  is the movement of plug stem  224  across the o-ring  230 . Again, because the plug stem  224  can be machined with greater precision than the plug cavity  215 , this arrangement substantially prevents the o-ring  230  from being destroyed or damaged by burs in the body  202 .  
      Additional properties which aid in providing a more reliable on/off valve  200  include the sizing and hardness of the body o-ring  230 . The body o-ring  230 , for instance, is preferably made of a high density material, such as Urethane of approximately 90° shore hardness. The preferred o-ring  230  is also relatively small, such as approximately a size 003 o-ring. Unlike a large, pliable o-ring  128 , a small, hard o-ring will not expand significantly as a result of the presence of CO 2 . The body o-ring  230  therefore retains its circular shape.  
      Additional o-rings  226 ,  226 A provide additional sealing, redundancy, and dust protection. Specifically, plug o-rings  226 ,  226 A prevent dust or other foreign substances from entering the valve assembly around the plug and provide redundancy by preventing leaks when the inlet o-ring  230  becomes worn or damaged. They also prevent leakage from the outlet  220  through the plug ends.  
      In another on/off valve  200 A, shown in  FIG. 12 , the flow aperture  225  can be moved into, and out of, fluid communication with the inlet  210  and outlet  220  by pushing or pulling the plug  220 A, rather than by rotation, as with the plug  220 . A guide pin can be provided to prevent rotation of the plug stem  224  and maintain the flow aperture  225  in a proper relationship with the inlet  210  and the outlet  212 .  
      A body o-ring  230 A can also be located within an entry port  213  to the gas outlet  212 , as schematically illustrated in  FIG. 13 . This o-ring  230 A can be provided in addition to, or instead of, the body o-ring  230  located in the exit port  211  of the gas inlet  210 . If sized and configured correctly, locating an o-ring  230 A in the entry port  213  of the outlet  212  can provide many of the same benefits as locating the o-ring  230  within the exit port  211  of the inlet  210 . If the flow aperture  225  in the plug  224  is made smaller than the outlet  212 , the gas pressure (represented by pressure arrows  224 ) coming from the flow aperture  225  will tend to expand outward from the exit of the flow aperture  225  and force the o-ring  230 A into a good sealing contact between the plug  224  and the valve body  202 B. Some problems with this embodiment, however, include the difficulty of machining an o-ring retention area in the entry port  213  of the outlet  212 , and the corresponding increase in expense. The body  202 B could be formed in two halves and then secured together to reduce the complexity of the required machining, but the body  202 B would then be bulkier and still more expensive.  
      The flow aperture need not be a hole through the center of the plug. The flow aperture, for instance, could be a groove around the outside of the plug, or any other type of aperture which would selectively allow gas to flow between the inlet and the outlet based on actuation of the valve. Despite the improvements in on/off valves provided by Perry et al., existing on/off valves have not provided an integrated fill nipple, such as is used for filling high pressure compressed gas tanks.  
     SUMMARY OF THE INVENTION  
      According to a preferred embodiment of the present invention, an on/off valve includes an integrated fill nipple. More particularly, a single spool, plug, or other valve member can be configured to provide a fill nipple for filling a compressed gas tank as well as an on/off valve for selectively supplying compressed gas from the compressed gas tank to a connected paintball gun.  
      The internal configuration of the on/off valve according to a preferred embodiment of this invention preferably includes the beneficial structural characteristics of Perry et al. Unlike the on/off valve of Perry et al., however, the plug, spool, or other valve member of a preferred embodiment of this invention also preferably includes an integrated fill nipple. The fill nipple and on/off valve can operate such that when the on/off valve is in either an on or off position, the fill nipple can be used to direct compressed gas from a compressed gas source into the tank to fill the tank. When the on/off valve is in an on position, compressed gas is preferably supplied from the compressed gas tank to a connected device, such as a paintball gun.  
      The foregoing and other features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention which proceeds with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a front, right side perspective view of a paintball gun with a compressed gas source, showing the general location of an on/off valve according to the prior art;  
       FIG. 2  is an enlarged side view of the on/off valve of  FIG. 1 ;  
       FIG. 2A  is a side view of an on/off valve for a paintball gun, similar to  FIG. 2 , according to another configuration of the prior art;  
       FIG. 3  is a bottom, right side perspective view of the prior art on/off valve for a paintball gun shown in  FIG. 2A ;  
       FIG. 4  is a horizontally cross-sectioned bottom plan view of the prior art on/off valve of  FIG. 3 , with a cutaway view of an o-ring configuration and a front elevation view;  
       FIG. 5  is a vertically cross-sectioned enlarged right side elevation view of a section of the prior art on/off valve of  FIG. 3 ;  
       FIG. 6  is an enlarged front elevation view and a cutaway left side elevation view of a plug for use in the prior art on/off valve of  FIG. 3 ;  
       FIG. 7  is a horizontally cross-sectioned bottom plan view and a vertically cross-sectioned front elevation view of a valve body for use in the prior art on/off valve of  FIG. 3 ;  
       FIG. 8  is a horizontally cross-sectioned bottom plan view and a front elevation view of an on/off valve for a paintball gun according to an improved prior art on/off valve design;  
       FIG. 9  is a vertically cross-sectioned enlarged right side elevation view of a section of the prior art on/off valve for a paintball gun of  FIG. 8 ;  
       FIG. 10  is an enlarged front elevation view and a cutaway left side elevation view of a plug for use in the prior art on/off valve of  FIG. 8 ;  
       FIG. 11  is a horizontally cross-sectioned bottom plan view and a vertically cross-sectioned front elevation view of a valve body for use in the prior art on/off valve of  FIG. 8 ;  
       FIG. 12  is a schematic side view of a combination fill nipple and on/off valve according to one embodiment of the present invention, shown connected to a paintball gun;  
       FIG. 13  is a schematic perspective view of the combination fill nipple and on/off valve of  FIG. 12 , shown connected to a compressed gas tank, wherein the valve body is shown transparently to permit viewing of the fill nipple and valve spool;  
       FIG. 14  is an enlarged perspective view of the combination fill nipple and on/off valve of  FIG. 13 , shown removed from the compressed gas tank with the valve in the off position, wherein the valve body is shown transparently to permit viewing of the fill nipple and valve spool;  
       FIG. 15  is an enlarged perspective view of the combination fill nipple and on/off valve of  FIG. 13 , shown removed from the compressed gas tank and with the valve in the on position, wherein the valve body is shown transparently to permit viewing of the fill nipple and valve spool; and  
       FIG. 16  is a cross-sectional view of an integrated on/off valve and fill nipple according to an embodiment of this invention. 
    
    
     DETAILED DESCRIPTION  
      A preferred embodiment illustrating the present inventive principles will now be described with reference to the accompanying figures. More specifically,  FIG. 12  is a schematic side view of a combination fill nipple and on/off valve  1000  according to a presently preferred embodiment of the present invention, shown connected to a paintball gun  50 .  FIG. 13  is a schematic perspective view of the combination fill nipple and on/off valve  1000  of  FIG. 12 , shown connected to a compressed gas tank  60 . In  FIG. 13 , the valve body  1001  is shown transparently to permit viewing of a fill nipple and valve spool  1010 .  FIGS. 14 and 15  are enlarged perspective views of the fill nipple and on/off valve  1000  shown in the “off” and “on” positions, respectively. And finally,  FIG. 16  is a cross-sectional view of the integrated on/off valve and fill nipple  1000  of  FIG. 13 .  
      Referring to  FIGS. 12-16 , according to a preferred embodiment of the present invention, an on/off valve and integrated fill nipple  1000  are integrally provided. More particularly, the on/off valve and fill nipple can be integrated for filling a compressed gas tank into a valve member (such as a spool or plug)  1010  for selectively supplying compressed gas from the compressed gas tank  60  to a connected paintball gun  50 . The internal configuration of the on/off valve portion  1020  according to a preferred embodiment of this invention preferably includes the beneficial structural characteristics of Perry et al. Unlike the on/off valve of Perry et al., however, the plug, spool, or other valve member  1010  of a preferred embodiment of this invention also preferably includes an integrated fill nipple  1012 . The fill nipple and on/off valve  1000  can operate such that when the on/off valve is in either an on or off position, the fill nipple  1012  can be used to direct compressed gas from a compressed gas source (not shown) into the tank  60  to fill the tank. When the on/off valve is in an on position, compressed gas is preferably supplied from the compressed gas tank  60  to a connected device, such as a paintball gun  50 .  
      The integrated fill nipple and on/off valve  1000 , shown in  FIGS. 12-16 , provides a further improvement in the art by combining a reliable on/off valve  1020  for a paintball gun  50  with an integrated fill nipple  1012 , thus reducing the space required for these components. More specifically, the integrated fill nipple and on/off valve  1000  has a valve body  1001  with a plurality of gas apertures. The gas apertures include a gas inlet  1021  configured to receive a gas from a pressurized gas source, and a gas outlet  1022  configured to transmit the gas to a paintball gun  50 . An actuator  1030  is configured to selectively control the flow of gas from the gas inlet to the gas outlet. Seals (e.g., seal  1021 a) may be located inside a port of one or more of the apertures to prevent the gas from leaking. A fill nipple  1012  is further preferably arranged on a valve member  1010  (such as a spool or plug).  
      In operation, the valve member  1020  is switched between an open (“on”) position and a closed (“off”) position by actuation of the actuator  1030 , which in turn moves the valve member  1020 . In an open position, the flow of gas is permitted between the gas inlet  1021  and the gas outlet  1022 . In a closed position, the flow of gas is interrupted. The seals (e.g., seal  1021   a ) operate to prevent gas from leaking from the port in which they are located. The seal  1021   a  performs its sealing function when the valve is in its open position as well as when it is in its closed position. In addition, the fill nipple  1012  preferably provides a one-way flow path into the compressed gas storage tank. The fill nipple  1012  can be configured to permit filling regardless of the position of the valve member  1020 . Alternatively, the fill nipple  1012  can be configured to permit filling only when the valve member  1020  is in a desired one of the actuated or deactuated positions.  
      As stated previously, the integrated fill/nipple and on/off valve  1000  preferably includes a valve body  1001  with gas apertures including a gas inlet  1021  and a gas outlet  1022 . These two apertures each preferably extend longitudinally through the body transverse to a plug cavity  1002 . The plug cavity  1002  preferably extends laterally through the body  1001  from one side to the other, and is located longitudinally between the inlet  1021  and the outlet  1022 . A plug  1010  is preferably positioned within the plug cavity  1002 . An actuator  1030  (such as a knob, lever, or other actuator) is preferably provided on an external portion of one end of the plug  1010 . In this particular embodiment, the actuator  1030  is a knob or handle that is physically attached to a plug stem  1010 . The plug stem (or spool)  1010  preferably extends into and through the plug cavity  1002  from the one side of the valve body  1001  to an opposite side. A flow aperture  1023  is preferably provided through the plug stem  1010  at the lateral position of the inlet  1021  and the outlet  1022  to fluidly connect the inlet  1021  to the outlet  1022  when the valve actuator  1030  is positioned in the “on” position. The actuator  1030  can preferably be rotated 90° to turn the valving mechanism  1020  “on” or “off”.  
      Two o-rings  1020   a,    1020   h  preferably extend around the plug stem  1010  within grooves  1025   a,    1025   h  arranged on opposite lateral sides of the inlet  1021  and outlet  1022 . The o-rings  1020   a,    1020   h  prevent gas from leaking out through the plug ends and ensure that the gas from the gas inlet  1021  travels to the gas outlet  1022  when the valving mechanism  1020  is open or “on.” They also provide redundancy and dust protection. When the actuator  1030  is located in an “on” position, the flow aperture  1023  is arranged in fluid communication with both the inlet  1021  and the outlet  1022  in order to permit a flow of the gas from the inlet  1021  to the outlet  1022 .  
      A body o-ring  1021   a  is preferably provided within the valve body  1001 . Specifically, the body o-ring  1021   a  is preferably located inside either an exit port  1021 h of the gas inlet or in an entry port (not shown) of the gas outlet  1022 . In this specific embodiment, the body o-ring  1021   a  is located in the exit port  1021   h  of the inlet  1021 . The body o-ring  1021   a  provides a seal between the valve body  1001  and the plug stem  1010 , and prevents gas from leaking out of the inlet  1021 . Because the o-ring  1021   a  surrounds the inlet  1021  of the valve body  1001 , it helps prevent gas leakage regardless of the position of the actuator  1030 . It preferably performs its sealing function when the actuator  1030  is the “on” position (open valve) as well as when it is in the “off” position (closed valve).  
      This configuration prevents the body o-ring  1021   a  from moving relative to the valve body  1001  and thereby substantially eliminates the risk of the body o-ring  1021   a  being cut or damaged by burs in the body  1001 . This is particularly advantageous because it is easier to machine the plug stem  1010  to remove burs than to remove burs from the surface of the plug cavity  1002 . Accordingly, movement of the finely-machined plug stem  1010  in relation to the body o-ring  1021   a  is much less likely to damage the o-ring  1021   a  than the movement of a plug o-ring in relation (not shown) to the body  1001 . The body o-ring  1021   a  will therefore have a significantly longer life than the prior art plug o-ring and provide a more reliable on/off valve.  
      In operation, the valve mechanism  1020  is switched between an open (“on”) position and a closed (“off”) position through 90° rotation of the plug  1010  via the actuator  1030 . In an open position, the flow aperture  1023  is arranged in communication with the inlet  1021  and permits a flow of gas from the inlet  1021  to the outlet  1022 . In a closed position, the communication between the flow aperture  1023  and the inlet  1021  is severed because the flow aperture  1023  is then positioned transverse to the longitudinal axes of the inlet  1021  and outlet  1022 . The body o-ring  1021   a  provides a seal between the valve body  1001  and the plug  1010  when the valve member  1020  is in either the open or the closed position. In the open position, the seal  1021   a  ensures the gas will travel through the flow aperture  1023 . In a closed position, the seal  1021   a  retains the gas within the inlet  1021 .  
      Gas pressure from the pressurized gas tank  60  can enhance the sealing properties of the body o-ring  1021   a  by encouraging the o-ring  1021   a  into physical communication with the plug  1010 . Also, if the o-ring  1021   a  is located in the valve body  1001 , rather than along the surface of the plug stem  1010 , then rotation of the plug  1010  does not substantially move the o-ring  1021   a  in relation to the valve body  1001 . Accordingly, in this particular configuration, the only movement of consequence for the body o-ring  1021   a  is the movement of plug stem  1010  across the o-ring  1021   a.  Because the plug stem  1010  can be machined with greater precision than the plug cavity  1002 , this preferred arrangement substantially prevents the o-ring  1021   a  from being destroyed or damaged by burs in the body  1001 .  
      Additional properties which can aid in providing a more reliable valving mechanism  1020  include the sizing and hardness of the body o-ring  1021   a.  The body o-ring  1021   a,  for instance, is preferably made of a high density material, such as Urethane of approximately 90° shore hardness. The body o-ring therefore preferably retains its circular shape.  
      Additional o-rings can be included to provide sealing, redundancy, and dust protection. Specifically, plug o-rings (e.g., o-rings  1010   a,    1020   a,    1020   h ) prevent dust or other foreign substances from entering the valve assembly  1020  around the plug  1010  and provide redundancy by preventing leaks from the plug cavity  1002  when the inlet o-ring  1021   a  becomes worn or damaged. They can also help prevent leakage from the outlet  1022  through the plug ends. Of course, the flow aperture  1023  need not be a hole through the center of the plug  1010 . The flow aperture  1023 , for instance, could be a groove around the outside of the plug  1010 , or any other type of aperture or flow path which would selectively allow gas to flow between the inlet  1021  and the outlet  1022  based on actuation of the valve mechanism  1020 .  
      The primary benefits resulting from the integration of the fill nipple  1012  with the on/off valve  1020  according to the principles of the present invention include space and weight savings which present important considerations in paintball guns. In addition, the preferred integrated fill nipple and on/off valve  1000  includes a balanced pressured shaft  1010  that can rotate the output air on and off while maintaining constant flow through the input side with the fill nipple  1012 . Integration of the fill nipple  1012  with the on/off valve  1020  also reduces the number of components required (e.g., eliminating a drive hex and thread along with other components) for less expensive and easier assembly as well as a cleaner installation and a lower profile. Combining the two components also enables faster assembly.  
      According to one additional design consideration, fill speed can be regulated by modifying the flow rate through the fill nipple  1012 . This can be accomplished, for example, by changing the diameter of the port  1011  passing through it. Reducing the flow rate can prevent over-stressing the tank  60  that may result from filling the tank  60  too fast.  
      Having described and illustrated the principles of the invention, it should be apparent that the invention can be modified in arrangement and detail without departing from such principles. We claim all modifications and variations coming within the spirit and scope of the following claims.