Abstract:
A pneumatic gun firing ram for firing one or more paintballs. The paintball gun includes a body defining a bore, with the bore being in communication with a valve for selectively releasing compressed gas to fire a paintball. A piston is located within the bore, and a rod is mounted within the piston for sliding movement. A hammer is mounted on an end of the rod opposite the piston, the hammer being movable between a first position and a second position relative the piston. A clamp substantially surrounds the rod at a region adjacent the hammer, and a pneumatic valve is adapted to move the pneumatic ram from a first position in the bore at a distance from the poppet valve to a second position in the bore proximate the poppet valve. The clamp is adapted to hold the pneumatic ram in the first position until sufficient pressure has built up to cause the pneumatic ram to overcome the clamp, causing the pneumatic ram to strike the poppet valve, thereby releasing the pressurized gas stream and driving the projectile from the gun.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]     This application is an application claiming the benefit under 35 USC 119(e) U.S. Application 60/529,194, filed Dec. 12, 2003, incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to a compressed gas powered gun for firing marking pellets or paint balls. More particularly, the present invention relates to rams for loading paint balls into a paint ball gun&#39;s proper firing position.  
       BACKGROUND OF THE INVENTION  
       [0003]     A variety of guns using discharged compressed gas for firing relatively fragile projectiles are known for employing manual, semi-automatic, and fully automatic arrangements. Compressed gas powered guns are typically useful as pellet marking guns, commonly called paint ball guns. Paint ball guns have attained widespread use in a recreational sport known as paint ball or war games. Typically located in open spaces with varying types of terrain, opposing sides employ guerilla-type strategy to seek out and “kill” one another by marking the opposition with a paint ball which is fired from a gun and bursts on impact.  
         [0004]     Paint ball guns use compressed gas to fire a gelatinous capsule containing a marking material. The marking capsules (paint balls) typically enclose a mixture of water and vegetable coloring so they are not toxic and can be removed from clothing and other surfaces with simple water washing. The capsule breaks on impact with the target dispersing the material to mark the target, for example an opposing player, where hit by the capsule. However, the marking capsule must have sufficient rigidity to avoid breakage during loading and firing operations of the gun.  
         [0005]     In U.S. Pat. No. 5,280,778, issued to Kotsiopoulos, a compressed gas powered gun is disclosed having a semi-automatic firing mechanism for enabling successive firing sequences. The firing mechanism includes a sear having a latch arm, with a cam at one end and an interlocking element at the other end. The cam is positioned to close a firing chamber as the latch arm is rotated. The interlocking element is positioned to concomitantly release an actuating bolt as the latch arm is rotated. A recoil spring repositions the actuating bolt for engagement with the interlocking element upon discharge of the firing chamber.  
         [0006]     Operation of the trigger of this gun first releases the hammer to fire a paint ball and subsequently switches a valve to re-cock the gun. Thus correct operation requires these two stages to achieve correct operation of the trigger. The timing of these two stages is also dependent upon the speed of trigger operation.  
         [0007]     Conventional paint ball guns include a loading ram for loading individual paint balls into a proper firing position inside the paint ball gun. Conventional rams, though having satisfactory performance capabilities, nevertheless include a number of deficiencies. In particular, conventional rams generate a relatively large amount of friction during use. This causes the ram to operate at a relatively slow speed. Additionally, conventional rams are also prone to suffer leakage of compressed gas during use.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a compressed gas paint ball gun in which the operating cycle is tripped by a trigger operated micro-switch and is subsequently controlled by a programmed electronic control circuit. This avoids the possibility of the cycle not being properly completed or being started again before it has been properly completed.  
         [0009]     The present invention provides a paint ball gun which has a first pressurized gas circuit for delivering pressurized propellant gas from a supply to the barrel of the gun. A valve in the first pressurized gas circuit is opened by a pneumatic device which is itself powered from a second pressurized gas circuit feeding from the same supply. A programmed electronic control circuit including a timer operates the pneumatic device. The electronic control device is actuated to begin the firing cycle by means of a switch connected to the trigger of the gun.  
         [0010]     The present invention comprises a pneumatic ram having a cylinder mounted within a cylindrical bore of the gun. The pneumatic ram includes a piston mounted on a rod for sliding movement in the cylinder. A hammer is mounted on one end of the rod for sliding movement therewith inside the bore. An o-ring is positioned around the rod at a location adjacent the hammer. When the hammer is in a first or retracted position, the o-ring is located within the cylinder and forms a seal therewith, behaving in a manner similar to a snap ring. When the hammer moves towards a second or extended position, the o-ring moves outside cylinder. This arrangement permits the ram to move from the retracted position to the extended position and vice versa much more rapidly than conventional pneumatic rams for paintball guns, due in part to the low friction between the rod and the cylinder. Additionally, the o-ring does not form a seal until the hammer is fully retracted, and the hammer can remain fully retracted without leaking gas. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     An embodiment of the invention is described below by way of example with reference to the accompanying drawings, in which:  
         [0012]      FIG. 1  is a side view of a paint ball gun with a hopper attached;  
         [0013]      FIG. 2  is a rear view of the paint ball gun of  FIG. 1  with the hopper removed and the breech in the open position;  
         [0014]      FIG. 3  is a sectional view of a conventional paint ball gun in a first condition;  
         [0015]      FIG. 4  is a sectional view of the paint ball gun of  FIG. 3  when in a second condition;  
         [0016]      FIG. 5  is an exploded side view of the components of the paintball gun of  FIG. 3 , including a prior art pneumatic ram;  
         [0017]      FIG. 6  is a sectional side view of a conventional, prior art ram in an extended position;  
         [0018]      FIG. 7  is a sectional side view of the prior art ram of  FIG. 6 , with the ram in a retracted position;  
         [0019]      FIG. 8  is a sectional side view of a ram according to the present invention, wherein the ram is in an extended position;  
         [0020]      FIG. 9  is a sectional side view of the ram of  FIG. 8 , with the ram in a retracted position; and  
         [0021]      FIG. 10  is a side view of a ram according to another embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     Referring to  FIGS. 1-5 , a conventional paintball gun  1  includes a main body  2 , with a grip frame  3 , a barrel  4  and a gas inlet regulator body  5  attached. A paint ball hopper  6  can be mounted on the top of the main body  2 .  
         [0023]     The grip frame  3  houses an electronic circuit board  7  which carries an electronic programmed control circuit for the gun including a programmed integrated circuit (PIC)  77 , a pivotally mounted trigger  8  and a micro-switch  9  for the control circuit which is actuated by the trigger  8 . The electronic control circuit is part of an electric circuit for the gun  1  which is powered from a battery  10  (shown in  FIG. 5 ) housed in the main body  2  through an isolator switch  11 . The electronic control circuit has a fixed cycle of operation which is governed by a timer.  
         [0024]     The gun  1 , which uses a gas propellant and a source of pressurized gas such as compressed air at about 800-850 psi, must be connected to the inlet  12  of the regulator body  5  either directly or through a supply line. The body  5  houses a gas pressure regulator which controls the gas pressure within the body chamber  13  to about 400-600 psi. The body chamber  13  is connected by a pipe  14  and a passageway  15  to a high pressure chamber  16  in the gun body. The high pressure chamber  16  is formed in a generally cylindrical bore  17  running the length of the main body  2  and is closed at one end by a bang valve or poppet valve  18  and at the other end by a second gas pressure regulator  19 . When the poppet valve  18  is opened it connects the high pressure chamber  16  with the barrel of the gun  4  as described below to form a first pressurized gas circuit for delivering pressurized propellant gas from the supply to the barrel  4  of the gun  1  for propelling paint balls therefrom. The second regulator  19  is a low pressure regulator which bleeds off “low pressure” gas at about 80-90 psi from the high pressure chamber  16  for use in a second pressurized gas circuit which forms the pneumatic control circuit of the gun  1  to be described below.  
         [0025]     The low pressure gas is conducted from the left hand end of the regulator  19  (as seen in  FIG. 3 ) through a drilled bore in the body  2  and fed to the inlet  20  of a control valve in the form of a spool valve  21  mounted in a second cylindrical bore  22  in the housing  2 . The spool valve  21  has a spindle  23  and a pair of servos  24 ,  25  mounted at either end of the valve  21  to act on the spindle  23 . A boring in the spool valve  21  delivers the low pressure gas to both of the servos  24 ,  25 , but because the servo  25  is more powerful than the servo  24 , it normally urges the spindle  23  to the left in  FIG. 3 .  
         [0026]      FIGS. 3-6  show in detail a conventional pneumatic ram  99  having a cylinder  26  mounted in the cylindrical bore  17  generally beneath the spool valve  21 . The pneumatic ram  100  has a piston  27  mounted on a rod  28  for sliding movement in the cylinder  26  and a hammer  29  mounted on an end of the rod  28  opposite the piston  27  for sliding movement within the cylinder  26  in the cylindrical bore  17 .  
         [0027]      FIG. 5  shows an exploded view of the paintball gun of  FIG. 4 , with the gun  1  including the conventional, prior art pneumatic ram  99 .  FIGS. 6-7  show the conventional, prior art pneumatic ram  99  in detail. One end of the rod  28  includes a notch  91  by means of which the rod  28  is releasably held in an adjustable clamp  93  comprising an o-ring  80  and an adjusting screw  81 .  
         [0028]      FIGS. 8-9  show a pneumatic ram, shown generally at  100 , constructed according to the present invention. Like the conventional, prior art pneumatic ram  99 , the pneumatic ram  100  of the present invention includes a piston  27  mounted on a rod  28  for sliding movement in the cylinder  26 . The hammer  29  is mounted on one end of the rod  28  opposite the piston  27  for sliding movement inside the cylinder  26 . The hammer  29  can have a nonuniform diameter, as shown in  FIG. 10 , so as to reduce the weight of the hammer  29 . A bumper  110  may also be included on the rod  28  for absorbing some of the impact of the cylinder  26  against the hammer  29 . A piston seal  102  is also positioned around the piston  27  for contacting and forming a seal with the cylinder  26 . An o-ring  104  is positioned around the rod  28  at a location adjacent the hammer  29 . When the hammer  29  is in a retracted position (shown in  FIG. 9 ), the o-ring  104  is located within the cylinder  26  and forms a seal therewith, behaving in a manner similar to a snap ring. Additional o-rings  112  may be placed along the outside of the cylinder  26  to provide additional sealing capabilities. According to one embodiment of the invention, the outside of the cylinder  26  may include a plurality of threads  114  (shown in  FIG. 10 ) to secure the pneumatic ram  100  to the cylindrical bore  17 . Other securing mechanisms known to those skilled in the art could also be used.  
         [0029]     When the spool valve  21  of  FIG. 3  is in the retracted position, low pressure gas supplied to the valve  21  is directed through valve outlet  30 , a space  31  and a forward port  32  to the cylinder  26  on the left hand side of piston  27  to urge the ram  100  to the retracted position shown in  FIG. 9 . In this position, the cylinder  26  to the right of the piston  27  is vented through a rearward port  33 , a space  34 , the valve outlet  35  and a vent valve  361 .  
         [0030]     An electrical solenoid switch is mounted on the servo  25  and can be actuated by the electronic control circuit of the gun to vent the servo  25  to atmosphere. In this condition, the servo  24  prevails to move the spindle  23  of the spool valve  21  to the right in  FIG. 3 . In this position the low pressure gas supply is directed through the valve outlet  35 , the space  34  and the rearward port  33  to the cylinder  26  onto the right of the piston  27  in  FIG. 3  to move the ram  100  to the left in  FIG. 3  towards its forward or extended position shown in  FIGS. 4 and 8 , where the hammer  29  engages the poppet  38  of the poppet valve  18  to open the poppet valve  18 . The left hand end of cylinder  26  is vented at this time through the forward port  32 , the space  31 , the valve outlet  30  and a further vent valve  362 .  
         [0031]     As shown in  FIG. 3 , the barrel  4  of the gun  1  comprises a third cylindrical bore  40  in the main body  2  coaxial with the second cylindrical bore  22  and a barrel extension  41  which is screwed into the third cylindrical bore  40 . A breech block  42  is pivotally mounted on the main body  2  between a closed position shown in  FIGS. 1, 3  and  4  and an open position shown in  FIG. 2 . The block  42  has a fourth cylindrical bore  43  which is aligned with the barrel  4  when the breech is closed and forms the rearmost part of the barrel  4 . A bolt  44  is mounted in the breech block  42  for sliding movement in the barrel  4  between the retracted position shown in  FIG. 3  in which it lies between the closed end  45  of the barrel  4  and a paint ball inlet  46  and a forward position shown in  FIG. 4  in which it closes the inlet  46 . The inlet  46  is provided by a pipe  47  which is screwed into the main body  2  and extends vertically upwardly to connect to the hopper  6 .  
         [0032]     The bolt  44  is generally cylindrical and is formed with an annular groove  48  and a plurality of axially extending bores  49  connecting the forward end of the bolt  44  with the groove  48 . A pin  50  mounted on the rearward end of the bolt  44  extends through a slot  51  in the breech block  42  and a slot  52  in the main body  2  into the cylindrical bore  17  where it locates in an annular grove  53  in the hammer  29 . Thus the bolt  44  is coupled to the ram  100  for movement therewith. Aligned ports  54  and  55  in the breech block  42  and the main body  2  connect the fourth cylindrical bore  43  with the inside of the poppet valve  18 .  
         [0033]     Operation of the gun  1  is as follows.  
         [0034]     With a source of high pressure gas connected to the inlet  12  of the gas inlet regulator body  5  and the on/off pin  56  pushed to the “on” position shown in  FIG. 3 , a high pressure gas charge exists in body chamber  13  and high pressure chamber  16 . Once the electrical switch  11  has been moved to the “on” position, the gun  1  is ready to fire. A paint ball fed down from the hopper  6  will be located in the barrel  4  adjacent the front end of the bolt  44  which will be in the retracted position shown in  FIG. 3 . When the trigger  8  is pulled, it operates the micro-switch  9  to actuate the electronic control circuit  7  and start the timer for the electronic control cycle. The electronic control circuit actuates the solenoid switch  37  to vent the servo  25 . The servo  24  then moves the spindle  23  of the spool valve  21  so that low pressure gas is delivered to the cylinder  26  to the right of the piston  27  and pressure in that part of the cylinder  26  begins to build. For a conventional, prior art ram  99  shown in  FIG. 6 , one end of the rod  28  is initially held in the adjustable clamp  93 . In  FIG. 3 , when the pressure in the cylinder  26  to the right of the piston  27  reaches a predetermined level, the rod  28  is released from the adjustable clamp  93  and the ram  99  can move to the left. The cylinder  26  space to the left of the piston  27  is now vented to atmosphere via the forward port  32 .  
         [0035]     In a pneumatic ram  100  according to the present invention, the o-ring  104  is initially positioned within the cylinder  26 , forming a seal therewith. At this point, the hammer  29  is in a retracted position. When the hammer  29  moves towards a second or extended position, the o-ring  104  moves outside the cylinder  26 . This arrangement permits the ram  100  to move from the retracted position to the extended position, and vice versa, much more rapidly than conventional pneumatic rams for paintball guns, due in part to the low friction between the piston seal  102  and the cylinder  26 . This is in contrast to the conventional, prior art pneumatic ram  99 , where friction is generated at other locations along the rod  28 . Additionally, the o-ring  104  does not form a seal until the hammer  29  is fully retracted, and the hammer  29  can remain fully retracted without leaking gas.  
         [0036]     In  FIG. 4 , the ram  100  slides rapidly to the left until the hammer  29  strikes the foot of the popper  38  of the poppet valve  17  to lift it from its seat and connect the high pressure chamber  16  with the breech block  42  through the valve  18  and aligned ports  54 ,  55 . This is the “firing” position shown in  FIG. 4 . As the ram  100  moves to its forward position, it carries the bolt  44  along with it. Thus the bolt  44  slides within the barrel  4  as the ram  100  advances, pushing the waiting paint ball past the inlet  46  and closing off the inlet  46 . When the hammer  29  opens the poppet valve  18 , the annular groove  48  in the bolt is aligned with ports  54 ,  55  and high pressure gas thus passes into the barrel  4  through the groove  48  and the axially extending bores  49  to propel the paint ball along the barrel  4  and out of its free end.  
         [0037]     After the poppet valve  18  has been momentarily opened by being struck by the hammer  29 , it closes under the action of gas pressure. A return spring  60 , pushes the ram  100  back a small way (about 1 mm) along the cylindrical bore  17  where it is held by the low pressure gas acting in the cylinder  26 .  
         [0038]     The bolt  44  remains in the forward position until the timer in the electronic control circuit actuates the solenoid switch  37  to close the vent of the servo  25 . Servo  25  moves the spool valve spindle  23  to the left in FIG.  3 , and gas pressure is directed through the spool valve  21  to the left side of the piston  27  to return the ram  100  to its retracted position shown in  FIG. 3 . The timer is set to return the ram  100  and the bolt  44  to the retracted position just as the paint ball is leaving the barrel  4 . At this point, a slight negative pressure exists in the barrel adjacent its closed end  45 , and as the bolt  44  retracts back past the inlet  46 , this negative pressure acts to help draw the next succeeding paint ball waiting in the pipe  47  into the barrel  4 . Once a further preset minimum time period has elapsed after the operation of the solenoid switch  37  to return the ram  100  and bolt  44  to their retracted positions, the cycle of the electronic control system is completed; and the electronic control circuit can be operated again by means of the trigger  8  to fire the next paint ball. A control knob  61  on the circuit board can be used to adjust the period of the cycle of the control circuit to vary the length of the cycle and thus the maximum number of shots which can be fired per second. This can normally be varied between about 5 and 15 shots per second. The point within the cycle at which the bolt  44  is withdrawn can also be adjusted by means of a second control knob  62 .  
         [0039]     The electronic timing of the return of the bolt  44  means that a disadvantage found in prior paint ball guns, where residual pressure in the barrel tends to blow the next succeeding paint ball back towards the hopper, is avoided. This has enabled the feed pipe  47  in the present gun  1  to be disposed vertically whereas in prior guns it has been necessary for the feed pipe  47  to enter the barrel  4  from the side.  
         [0040]     The hopper  6  is provided with an electrically driven stirring mechanism. A cable  70  from the hopper  6  to a socket  75  on the gun  1  connects the stirring mechanism to the electric circuit of the gun  1  so that its operation can be controlled by the electronic control circuit. Advantageously the stirring mechanism is actuated whenever the gun  1  is first switched on and at any time when the firing rate of the gun  1  exceeds a predetermined rate such as two shots per second.  
         [0041]     As described, the gun  1  is set up for semi-automatic operation, but it can readily be converted to select fire or fully automatic operation in which the electronic control circuit continuously repeats the firing cycle whilst the trigger  8  is actuated. In this case the rate of fire will depend solely on the length of the firing cycle.  
         [0042]     An LED  74  mounted on an end plate  71  warns the user that the gun  1  is switched on. The end plate  71  covers the bores  17  and  22  and a further cylindrical bore parallel to both bores  17 ,  22  which houses the battery  10 . A knob  72  adjacent the end plate is pulled to release a catch holding the breech block  42  in the closed position. The end plate  71  also supports the socket  75  which, apart from providing a power connection for the hopper stirring mechanism, can also be used as a charging socket for the battery  10 . Removal of the end plate  71  gives access to the adjusting screw  81  of the piston rod clamp.  
         [0043]     It should be understood that the term “low pressure” is used herein to refer to a working gas pressure which is generally lower than the high gas pressure used to fire the paint balls but is nevertheless a positive pressure higher than atmospheric pressure. The “high” pressure required in chamber  16  decreases if the size of the chamber  16  is increased and although a high pressure is not needed in the pneumatic control circuit, there is nothing to prevent a high pressure being used. Thus whilst it is preferred that the first pressurized gas circuit will be at a higher pressure than the second pressurized gas circuit as described, this is not essential and the two circuits could run at the same pressure.  
         [0044]     It should be understood that the above description of the invention and the specific examples and embodiments, while indicating the preferred embodiments of the present invention, are given by demonstration and not limitation. For example, it should be understood that the present invention could be used in conjunction with a many different varieties of paintball guns besides the particular embodiments described herein. The present invention may be used with paintball guns incorporating a wide range of parameters, including various operating pressures, paintball exit velocities, and component arrangements. Many changes and modifications within the scope of the present invention may therefore be made without departing from the spirit of the invention, and the invention includes all such inventions and modifications.