Abstract:
A paintball marker includes a housing having formed therein a cylindrical chamber with an axis and an open end, and a valve assembly within and coaxial with the chamber. The chamber wall has first and second openings. The valve assembly is configured so that, during one period of revolution about the axis, in a first portion the valve assembly closes the second opening while permitting entry of a ball into the chamber through the first opening, and in a second portion the valve assembly closes the first opening while permitting entry of compressed gas into the chamber through the second opening. The compressed gas entering the chamber during the second portion expels the ball through the open end of the chamber. Delivery of the ball to the housing, and delivery of compressed gas to expel the ball, requires only one moving part, namely the valve assembly revolving in the chamber.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    This disclosure relates to the recreational sport of paintball, and more particularly to a paintball marker device. 
       BACKGROUND OF THE DISCLOSURE 
     Paintball and Paintball Markers: 
       [0002]    Paintball markers are used in the sport and recreation of paintball to engage in strategic field tactics against opposing players. Similar to the game of tag, this action pursuit game is generally played as two opposing teams seek to eliminate rival players with paint marks. Each participant (paintball player) uses a paintball marker to precisely fire a paintball projectile intended to burst on the target, leaving a distinct paint mark. Paintball markers propel a paintball projectile, typically a round gelatin-filled ball with non-toxic, washable paint, at a sufficient muzzle velocity so that its capsule breaks on impact within range. 
         [0003]    Most paintball markers operate with the assistance of air, nitrogen, or carbon dioxide. Because of the energy generated as these gases exceed atmospheric pressure, compressed gases are commonly used to propel a paintball projectile out the firing chamber and through the barrel of paintball markers. These gases are commonly stored inside the paintball marker apparatus with adequate pressure to achieve the desired muzzle velocity and proper functional operation when fired. The stored energy in the compressed gas is thus transferred to the paintball projectile when the paintball marker fires the projectile; the supply of projectiles and compressed gas is depleted during operation of the paintball marker. 
         [0004]    Changes in paintball marker technology have shaped the development of the sport itself. Improvements in paintball markers&#39; speed, accuracy, air efficiency, reliability, ergonomics, aesthetics, and audibility have helped to popularize the sport. Avid paintball players continuously research new and improved paintball marker designs. 
       Paintball Marker Selection Criteria: 
       [0005]    Paintball players may consider numerous technical and aesthetic criteria when selecting a paintball marker, including the following: 
         [0006]    Speed (rate of fire): The speed of a paintball marker is measured in paintballs fired per second; 15-20 balls per second is a typical speed. 
         [0007]    Firing modes: Semi-automatic, 3-burst, full-automatic, and other firing modes are available. 
         [0008]    Accuracy: Several factors influence the accuracy of a paintball marker. It is desirable to minimize recoil, for better overall accuracy and better firing stability. High “ball on ball” precision (the precision of paintball splats on the target) is desired; ideally the paintballs hit on top of one another on the target. Precise muzzle velocity is also desired; ideally the muzzle velocity (measured by a chronograph) will have a precision within +/−2 feet per second. “Drop-off” (decrease in muzzle velocity at higher rates of fire) should be kept to a minimum. 
         [0009]    Air efficiency: Air efficiency is measured by the number of shots that can be discharged with a full tank of compressed gas. Less consumption of compressed gas per shot allows the player to stay longer on the playing field without having to refill the compressed gas tank. 
         [0010]    Reliability: “Chopping” and ball breakage must be avoided. Chopping refers to breaking paintballs in the breech before they are discharged from the breech to the barrel. Ball breakage is a general term for breaking paintballs inside the paintball marker before they exit the barrel. Breaking paintballs may ruin the on-field experience and may contribute to a forfeit. 
         [0011]    Operation and maintenance: It is desirable to have working parts made of durable materials. Fewer working parts contributes to longer life and ease of routine maintenance (lubricating moving parts, seals, etc.). Generally a more simple operation is easier to fix or troubleshoot. The method of operation of the paintball marker may contribute to the likelihood of a breakdown or malfunction. 
         [0012]    Ergonomics: A lighter weight paintball marker allows the user to quickly reengage opponents. “Snap-shooting” is a popular skill used on the field; this firing technique involves a quick shot before hiding behind cover, and is easier with a lightweight paintball marker. Generally a compact design of paintball marker is desired. The smaller the target size, the more likely a player will stay in the game and not be eliminated. Weight and size both contribute to overall firing technique and player endurance. 
         [0013]    Aesthetics: It is desirable to have a variety of colors, shapes, milling designs, etc. for different components of the paintball marker. Players often wish to customize their paintball markers by selecting from a variety of compatible parts. 
         [0014]    Audibility: Quiet operation is desirable because noise coming from the paintball marker can give away a position to an opponent. Also, a player can better communicate if there is reduced noise interruption from the marker. 
       Types of Paintball Markers 
       [0015]    There are two types of paintball markers: markers with hammers, and markers without hammers. 
         [0016]    Markers with hammers: These paintball marker designs typically use a hammer to thrust open a poppet sealed air valve held shut by a spring. A bolt, typically attached to the hammer, is responsible for loading and sealing the firing chamber while routing the compressed gas from the open valve to propel the paintball. The bolt and hammer reciprocate forward and backwards once while firing a single shot. In some markers, the hammer is driven electronically via an air solenoid, or mechanically via a sear and spring. Air solenoids operate with a dwell time, or the length of time the air valve can be opened. Most air solenoids can achieve a minimum of 6 ms (milliseconds) dwell time. 
         [0017]    Markers without hammers: These paintball markers use a “spool” with an array of O-rings to seal and contain gas pressure in a plurality of chambers. As the spool is moved or shifted forward, the compressed gas is redirected into new passageways and released to fire a paintball. Similar to markers with hammers, spool markers use a bolt-style design to load and fire a paintball. These operate mechanically or electronically with the assist of an electronic valve or air solenoid. 
         [0018]    Markers with air solenoids also require a low pressure regulator (LPR) to regulate the pressure to operate the air solenoid. If there is any variation in the pressure regulation from the LPR to the air solenoid, the paintball marker may discharge a paintball inaccurately. Specifically, relying on a LPR to regulate the air solenoid and open the valve may cause inconstant firing velocity, or low precision (poor “ball on ball” accuracy). Furthermore, markers with LPR and air solenoids are prone to drop-off. 
       Conventional Paintball Markers: 
       [0019]    Conventional paintball markers, particularly those with LPRs and air solenoids, have several drawbacks that can frustrate the player and disrupt the on-field experience, in particular: 
         [0020]    Accuracy: High recoil due to impact and movement from multiple moving parts. Parts reciprocate back and forth. Paintball is moving when fired. 
         [0021]    Air Efficiency: Compressed gas is used both to operate the firing mechanism and to propel the paintball. Some air solenoids have a minimum dwell time (length of time the air solenoid can throttle open the valve). Compressed air may be wasted due to an excessive dwell time. The ideal dwell time is 3.33 ms which cannot be achieved with conventional air solenoids used for paintball markers. Due to the limitations on air efficiency, larger compressed air tanks may be required. 
         [0022]    Reliability: Complex mode of operation, with multiple moving parts requiring lubrication; numerous O-rings, springs, and fasteners. Paintball marker can chop or break paintballs from their loading mechanisms (bolts reciprocate forwards to load a paintball into its firing position and can break them while doing so). Air solenoids may permanently fail if the input pressure spikes above its maximum pressure rating. Air solenoids have low maximum pressure ratings and are therefore prone to failure. 
         [0023]    Ergonomics: Number and complexity of working parts causes excess weight. Size is driven by the need to house the multiple working parts. 
         [0024]    Maintenance: Many different replacement components need to be purchased, e.g. air solenoids, valves, low pressure regulators, hoses, O-rings, air bolts, bolt pins, hammers, springs, etc. 
         [0025]    Audibility: Number and complexity of working parts causes excess noise during operation. 
         [0026]    Two recently issued patents further serve to illustrate features of conventional paintball markers. U.S. Pat. No. 7,735,479 to Quinn et al. discloses a paintball marker having a bolt, an impact ring within the bolt, and a striking surface contacted by the impact ring. U.S. Pat. No. 7,594,503 to DeHaan et al. discloses a paintball marker with a bolt and an air solenoid requiring a low-pressure regulator. 
       Desirable Improvements: 
       [0027]    It is desirable to implement a lightweight, compact, durable paintball marker having a minimum number of moving parts and that does not use a LPR linked to an air solenoid, and accordingly may offer improved accuracy, firing precision, air efficiency, reliability and ergonomics when compared to currently available paintball markers. 
       SUMMARY OF THE DISCLOSURE 
       [0028]    The present disclosure provides a paintball marker including a housing having formed therein a cylindrical chamber with an axis and an open end, and a valve assembly within and coaxial with the chamber. The chamber wall has first and second openings. The valve assembly is configured so that, during one period of revolution about the axis, in a first portion the valve assembly closes the second opening while permitting entry of a ball into the chamber through the first opening, and in a second portion the valve assembly closes the first opening while permitting entry of compressed gas into the chamber through the second opening. The compressed gas entering the chamber during the second portion expels the ball through the open end of the chamber. 
         [0029]    In an embodiment, the valve assembly includes a valve body and a scoop. The valve body has an axial slot therein for permitting entry of the compressed gas in the second portion of the period; the slot has sides extending in the axial direction and ends extending in the azimuthal direction. The valve body has protrusions at an exterior cylindrical surface thereof for contacting an inner surface of the chamber and thereby preventing escape of the compressed gas at the exterior of the valve; the protrusions form axially spaced circumferential seals at respective ends of the slot and longitudinal seals, each intersecting the circumferential seals, along respective sides of the slot. In this embodiment, the valve assembly further comprises a scoop for holding the ball; the scoop is attached to the valve body and coaxial therewith, and is configured to receive the ball entering the chamber in the first portion of the period and to close the first opening in the second portion of the period. The scoop is open at a front end thereof to permit movement of the ball as it is expelled, and has an opening at a rear end thereof communicating with an interior of the valve body, so that the compressed gas flows through that opening toward the ball in the second portion of the period. 
         [0030]    It will be appreciated that delivery of the ball to the housing, and delivery of compressed gas to expel the ball, requires only a single moving part, namely the valve assembly revolving in the chamber. 
         [0031]    The foregoing has outlined, rather broadly, the preferred features of the present disclosure so that those skilled in the art may better understand the detailed description of the disclosure that follows. Additional features of the disclosure will be described hereinafter that form the subject of the claims of the disclosure. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present disclosure and that such other structures do not depart from the spirit and scope of the disclosure in its broadest form. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIGS. 1A-1C  are respectively a front perspective view, a side view, and a rear perspective view of a paintball marker according to an embodiment of the disclosure. 
           [0033]      FIG. 2  illustrates a main housing and a revolving valve assembly with a motor, in a paintball marker according to an embodiment of the disclosure. 
           [0034]      FIGS. 3A-3C  are respectively a front perspective view, a rear perspective view, and a disassembled view of the revolving valve assembly and motor of  FIG. 2 . 
           [0035]      FIGS. 4A-4D  are respectively a front perspective view, a top view, a cross section view, and a rear perspective view of a revolving valve assembly according to an embodiment of the disclosure, including a front revolving chamber scoop and a rear revolving valve. 
           [0036]      FIG. 4E  is a detail view of  FIG. 4D , showing the home position marked on a sensor disc of the revolving valve assembly. 
           [0037]      FIGS. 5A and 5B  are respectively a cutaway view and a cross section view of the main housing of a paintball marker according to an embodiment of the disclosure. 
           [0038]      FIG. 6A  is a cross section of an assembled paintball marker according to an embodiment of the disclosure. 
           [0039]      FIG. 6B  is a detail view of  FIG. 6A , showing the interior of the main housing with a paintball loaded in the breech thereof. 
           [0040]      FIG. 7  is an exploded view of the paintball marker of  FIG. 6 . 
           [0041]      FIG. 8  illustrates the starting torque required to turn a PTFE revolving valve using press and shrink fit analysis. 
           [0042]      FIG. 9  illustrates the torque curve for a small-sized bipolar stepper motor used in embodiments of the disclosure. 
           [0043]      FIG. 10A  illustrates in cross section view the home position of the front revolving chamber scoop relative to the breech opening in the main housing of  FIGS. 5A and 5B . 
           [0044]      FIG. 10B  illustrates in cross section view the home position of the rear revolving valve relative to the compressed gas slot in the main housing of  FIGS. 5A and 5B . 
           [0045]      FIG. 10C  illustrates in cross section view the position of the front revolving chamber half a revolution from the home position, relative to the breech opening in the main housing of  FIGS. 5A and 5B . 
           [0046]      FIG. 10D  illustrates in cross section view the position of the rear revolving valve half a revolution from the home position, relative to the compressed gas slot in the main housing of  FIGS. 5A and 5B . 
       
    
    
     DETAILED DESCRIPTION 
       [0047]    A paintball marker  100  in accordance with the disclosure is shown in three separate views in  FIGS. 1A ,  1 B and  1 C. Marker  100  has a main housing  10 , into which is inserted a revolving valve assembly, discussed in detail below. The revolving valve assembly is driven by a motor  3  at the rear of the main housing. Paintballs are fed by gravity from a hopper (not shown) through feedneck  13  and into a breech portion of the main housing. Compressed gas from a tank (not shown), coupled to the marker at gas coupler  130 , is fed through 90° air swivel connector  30 , forward through a gas tube (not shown) and into air source adapter (ASA) regulator  40  through straight air connector  38 . Compressed gas fills a reservoir in housing  10 . The player holds the handle (integral with trigger guard  36 ) and squeezes the trigger  35  to discharge one or more paintballs. The revolving valve assembly is driven so that compressed gas from the reservoir meets the paintball inside the main housing; the paintball is discharged through barrel  46 . 
         [0048]    As shown in  FIG. 2 , the combination  110  of motor and valve assembly mates with main housing  10  at the rear thereof, so that valve assembly  150  is received in a cylindrical bore in the main housing (see also  FIGS. 5A and 5B ). Motor  3  connects to the rear of revolving valve assembly  150 . Combination  110 , which includes the motor and the revolving valve assembly, is shown in three separate views in  FIGS. 3A ,  3 B and  3 C. In  FIG. 3A , the revolving valve assembly is shown holding a paintball  4 . 
       Revolving Valve Assembly: 
       [0049]    Components of the revolving valve assembly  150  will now be described, with reference to  FIGS. 3A-3C  and  4 A- 4 E. This assembly includes front revolving chamber scoop  1  and rear revolving valve  2 . Front revolving chamber scoop  1  is shaped so that it holds the paintball at rest prior to the paintball being propelled through the barrel. Chamber scoop  1  is made of transparent material (e.g. acrylic or polycarbonate) to permit the electronic breakbeam eyes (described more fully below) to function. The scoop is located directly beneath feedneck  13 , so that as the paintball  4  feeds itself into the breech portion of the main housing  10 , the paintball  4  lands directly in the scoop  1  and remains in the chamber scoop until the paintball is discharged. Scoop  1  has an air exit hole  121  opening to the rear of the scoop along the axis of the valve assembly; compressed gas is discharged through this hole to propel the paintball through the barrel. In operation, the scoop revolves while the paintball is discharged, thereby closing the breech as compressed gas is discharged from the air exit hole. The scoop is sized according to the caliber of the paintball. In this embodiment, the scoop accommodates a 0.5 CAL paintball; other paintball calibers can be accommodated. Scoop  1  is attached to rear revolving valve  2  by chamber screws  9  (see  FIG. 3C ). 
         [0050]    Rear revolving valve  2  is typically made of polytetrafluoroethylene (PTFE, commonly branded as Teflon®). PTFE has an extremely low friction coefficient, which decreases with an increase of external force applied, and is frequently used in dynamic sealing applications. As illustrated in  FIGS. 3A-3C  and  4 A, the body of valve  2  is cylindrical, has air entrance slot  123  formed therein and has round seals  122  protruding slightly from the cylindrical surface. Air entrance slot  123  extends along the axis of the cylinder and typically is relatively narrow in the direction perpendicular to the axis (that is, the azimuthal direction). In this embodiment, the angular width of air entrance slot  123  is 30°. The round seals  122  trap compressed gas in a reservoir while the revolving valve is at rest. The round seals comprise two circumferential seals (that is, following the circumference of the cylinder in the azimuthal direction), axially spaced from each other at either end of air entrance slot  123 , and two longitudinal seals (parallel to the axis) on either side of the air entrance slot  123 . The two longitudinal seals prevent compressed gas from escaping to the air entrance slot when the valve is at rest and while the valve is in motion, except during a portion of the period of its revolution (the dwell time, as explained below) when the air entrance slot is open to the compressed gas reservoir. The two circular seals keep compressed gas sealed at all times, both while the valve is at rest and while the valve is in motion. 
         [0051]    As rear revolving valve  2  turns about its axis, a paintball resting in the front chamber scoop  1  is loaded to be discharged. The home position  126  for movement of the valve (marked on the IR sensor disc  124 ) corresponds to an open breech position where the scoop  1  faces upward towards breech opening  511  and thence towards the hopper, so that the scoop is ready for the next paintball to drop into it ( FIG. 10A ). When the revolving valve  2  and seals  122  are in the home position, air entrance slot  123  faces opposite to slot  520  in the main housing, so that compressed gas does not escape from reservoir  502  ( FIG. 10B ). After half a revolution (that is, after 25 milliseconds at a speed of 20 rps), scoop  1  faces downward, thereby sealing off the breech opening  511  ( FIG. 10C ). The two longitudinal round seals  122  are an appropriate angular distance apart (30° in this embodiment); as the valve turns and seals  122  sweep past slot  520 , compressed gas form reservoir  502  is allowed to enter through the air entrance slot  123  ( FIG. 10D ). This compressed gas exits through the air exit hole  121  with an appropriate dwell time depending on the angular velocity and angular separation of the longitudinal round seals. For example, if the valve turns at 20 revolutions per second (so that one period is 50 milliseconds) and the seals are 30° apart, the dwell time is approximately 4 milliseconds. Accordingly, for about 4 milliseconds during each period, compressed gas escapes from the reservoir and enters the interior of the valve body in a radial direction through slot  123 ; the compressed gas then escapes from the valve body in an axial direction through exit hole  121  to propel the paintball. 
       Torque and Gas Pressure: 
       [0052]      FIG. 8  gives the estimated starting torque required to move the PTFE rear revolving valve for various values of the radial squeeze or radial interference δ (that is, the amount by which the radius of the valve body, measured at the circumferential seals, exceeds the inside diameter of the bore in the main housing in which the valve turns). A radial squeeze of 0.002 inch corresponds to a total required starting torque of approximately 8 oz-in. In  FIG. 8 , starting torque and radial squeeze are related by 
         [0000]      {Starting Torque(oz-in)=91852*(Radial Squeeze(in.)) 1.506 }. 
         [0053]    At this radial squeeze, the maximum allowable radial pressure σ r  is approximately 260 psi. The radial squeeze and maximum allowable pressure are related by 
         [0000]      {Maximum Allowable Pressure(psi)=131000*(Radial Squeeze(in.)}. 
         [0000]    This means that a maximum of 260 psi of compressed gas can be used to fire a paintball with the radial squeeze value chosen. 
         [0054]    Alternatively, other revolving valve designs may include a removable O-ring device, use other related materials, etc. 
       Motor: 
       [0055]    As shown in  FIGS. 3A-3C , motor  3  drives revolving valve  2 , with the motor shaft received in motor shaft hole  125  at the rear of the valve body (see  FIG. 4D ). In this embodiment, motor  3  is a stepper motor, which can be precisely controlled to an accurate starting and stopping position. The motor shaft inserts into motor shaft hole  125  and is locked into place by motor shaft screw  8  ( FIG. 3C ). Appropriately sized stepper motors supply approximately 6 to 50 oz-in of torque output and are typically controlled with the use of a driver and microprocessor with multiple I/O commands.  FIG. 9  shows a torque curve for a stepper motor that may be used in this embodiment. As noted above, the required starting torque for the valve body in this embodiment is approximately 8 oz-in when the radial squeeze is 0.002 inch between the valve body and the main housing. The motor with the torque curve in  FIG. 9  can provide approximately 9 oz-in of torque at a speed of 20 revolutions per second. 
         [0056]    In other embodiments, a gear train may be used to adjust the desirable torque or speed output to the revolving valve. Other electronically driven, air-assisted, or manual rotational devices and mechanisms for turning the revolving valve may also be used. 
       Paintball: 
       [0057]    As noted above, paintball  4  rests in the front revolving chamber scoop  1  before being discharge by the compressed gas exiting from the rear revolving valve  2 . Current popular paintball sizes are 0.5 CAL and 0.68 CAL. Paintball  4  typically requires 150 to 300 psi of compressed gas to be propelled so as to achieve a muzzle velocity of 300 FPS (feet per second). The pressure required to obtain a desired muzzle velocity depends on the size and weight of the paintball. 
       IR Photosensor: 
       [0058]    In this embodiment, an IR photosensor  5  (see  FIG. 3B ) provides feedback for the circuitry of the motor controller. As shown in  FIG. 3B , the IR photosensor tracks the angular position of disc  124  and thus provides a “home position” signal to the controller. The home position  126  for revolution of the valve  2  is marked approximately one revolution from start to stop on the IR sensor disc  124 . The front revolving chamber scoop  1  is open to feed a paintball in this position. 
       Ball Detent: 
       [0059]    Ball detent  6 , typically rubber in material, is located at the interior wall of main housing  10  (the wall of the cylindrical chamber  510  in which the revolving valve assembly turns), protruding radially inward toward the front revolving chamber scoop. Ball detent  6  holds the paintball in place while the revolving valve  2  is at rest. As the revolving chamber turns, the front revolving chamber scoop pushes the ball detent beneath itself, so that the paintball is free to exit the breech when pushed by air escaping from air exit hole  121 . 
       Electronic Breakbeam Eye: 
       [0060]    One or more electronic breakbeam eyes  7  monitor the position of scoop  1  and sense the position of the paintball  4  (scoop  1  is made of a transparent material for this reason). The electronic breakbeam eyes determine whether the paintball is in the correct position to be discharged. If the paintball is not properly positioned, the electromagnetic beam is not broken; the circuit board detects a signal accordingly and the operation of the paintball marker will halt. The electronic breakbeam eyes are used to prevent the paintball marker from operating prematurely and decrease the chance of the paintball breaking inside the breech due to premature firing. 
       Main Housing Breech and Gas Reservoir: 
       [0061]      FIG. 5A  is a cutaway view of the main housing  10 .  FIG. 5B  is a cross section view of the main housing  10 , showing two parallel chambers having openings  461 ,  451  in the front face of the main housing. The upper chamber  510  is cylindrical and receives the revolving valve assembly through a rear opening  515 ; the valve assembly, driven by motor  3 , turns inside chamber  510 . A breech portion  501  has the front revolving chamber scoop  1  turning therein; paintballs from the hopper enter the breech through opening  511 . The lower bore (in this embodiment, a second cylindrical chamber) comprises compressed gas reservoir  502 . Reservoir  502  is plugged at the front end by front hole plug screw  45  (see  FIG. 7 ). Opening  503  receives the outlet of a gas regulator which supplies compressed gas to the reservoir. The cylindrical chambers communicate through a slot  520  which is blocked by the revolving valve  2  and the round seals  122 , except when in alignment with air entrance slot  123  of the revolving valve  2  (see  FIG. 10D ). 
         [0062]      FIGS. 10A-10D  illustrate opening and closing of the breech opening  511  and slot  520  during one revolution of the valve assembly.  FIGS. 10A and 10C  are cross sections of the chamber at breech  501 , while  FIGS. 10B and 10D  are cross sections of the chamber at slot  520 . As noted above,  FIGS. 10A and 10B  illustrate the home position of the revolving valve assembly, while  FIGS. 10C and 10D  illustrate the position of the revolving valve assembly half a revolution removed from the home position. 
       Paintball Marker: Assembled View 
       [0063]      FIG. 6A  is a cross section view of an assembled paintball marker in accordance with an embodiment of the disclosure. Paintball  4  (see detail in  FIG. 6B ) is shown at rest in the breech  501 , ready to be propelled down barrel  46 . Feedneck clamp  14  fastens and secures the paintball hopper (not shown) to feedneck  13  connecting to main housing  10 . Air Source Adapter (ASA) regulator  40 , connecting to reservoir  502 , regulates input pressure from the compressed gas tank (not shown) and outputs an adjusted pressure into reservoir  502 . The input of regulator  40  is connected to straight air connector  38 , which in turn connects to a gas tube (not shown) leading to the air source adapter having coupler  130  connecting to the gas tank. It will be appreciated that the mechanism for propelling the paintball has only one moving part, namely the revolving valve assembly driven by the motor  3 . Furthermore, all of the gas pressure from the regulator  40  supplied to reservoir  502  is expended in propelling the paintball; no gas is diverted to operating any mechanism. 
       Paintball Marker: Exploded View: 
       [0064]    Other components of the paintball marker in this embodiment are shown in  FIG. 7 . 
         [0065]    Eye covers  11  protect the electronic breakbeam eyes from debris and UV radiation. Eye cover screws  12  attach the eye covers  11  to the main housing  10 . 
         [0066]    Feedneck clamp screw  15  adjusts the tightness of the feedneck clamp  14 . 
         [0067]    O-ring  16  seals the trigger frame compartment and protects the electronics from harmful saturation exposure. Motor damper  17  reduces vibration from the motor  3 . Circuit board dampers  18  protect circuit board  19 . Circuit board  19  contains the driver (A3979 in this embodiment) and microcontroller (PIC24 in this embodiment) which operate stepper motor  3 . Circuit board screws  20  attach circuit board  19  to main housing  10 . Ball detent cover screw  21  secures ball detent  6  in position. 
         [0068]    Trigger switch  22 , which in this embodiment comprises an IR sensor, activates the firing operation. The firing operation is initiated when trigger adjustment screw  37  on trigger  35  interrupts the switch. Trigger switch  22  rests behind the trigger. Trigger switch magnet  23  and trigger magnet  39  use magnetic repulsion to return trigger  35  to a safe, non-firing position. Trigger frame screws  24  attach trigger frame  36  to main housing  10 . 
         [0069]    Grip covers  25  protect the batteries (3×9V in this embodiment) stored in the grip frame compartment of the trigger frame. Grip covers  25  also provide a secure gripping surface for the user. On/Off switch screw  26  attaches On/Off switch  34  to trigger frame  36 . Grip cover screws  27  attach grip covers  25  to trigger frame  36 . 
         [0070]    Trigger switch dowel pins  28  secure trigger switch  22  inside the trigger frame. Trigger dowel pin  29  acts as a pivot to trigger  35  and secures it in a swivel position in the trigger frame. 
         [0071]    90° air swivel  30  connects an external air tube to straight air connector  38  and routes compressed gas from the air source adapter  33  to ASA regulator  40 . ASA screws  32  attach the air source adapter  33  to the bottom of trigger frame  36 . 
         [0072]    On/Off LED light  31  lights up to indicate whether the marker is on or off. This light thus functions as a firing and safety mode indicator. On/Off switch  34  turns the paintball marker on and off, and also acts as a safety switch. Trigger adjustment screw  37  is adjusted to interrupt trigger switch  22  at a desired firing location during a trigger pull. Trigger adjustment screw  41  adjusts the magnetic repulsion length or trigger return length between the trigger frame magnet and the trigger magnet. 
         [0073]    Air slot cover plate  44  compresses air slot cover plate O-ring  43  to seal the main housing reservoir. Air slot cover plate screws  42  attach the air slot cover plate to the main housing. 
         [0074]    A paintball marker embodying the disclosure offers some significant benefits. Since there is only one moving part (the revolving valve assembly), there are no parts moving linearly or reciprocating. There are no mechanical switches or levers. The paintball is at rest when it is fired. Compressed gas is only used to propel a paintball, not to operate the firing mechanism. By adjusting the speed of the revolving valve, it is possible to achieve a desired dwell time, without relying on the timing of an air solenoid or mechanical parts. Since no air solenoid is required to operate the paintball marker, a smaller compressed air tank may be used. This will lighten the overall load on the player. 
         [0075]    The simplicity of operation, owing to a single moving part, ensures a high level of reliability. Furthermore, no lubrication is necessary, and no springs or O-rings are required. Since there is no force on the paintballs while loading them into the breech, there is less likelihood of paintball breakage. 
         [0076]    A paintball marker according to an embodiment of the disclosure may be lightweight and have a compact body design. In addition, the marker is inexpensive to produce, due to low material costs. A marker embodying the disclosure can be injection molded to further reduce manufacturing costs. No upkeep or maintenance costs are needed. 
         [0077]    While the disclosure has been described in terms of specific embodiments, it is evident in view of the foregoing description that numerous alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the disclosure is intended to encompass all such alternatives, modifications and variations which fall within the scope and spirit of the disclosure and the following claims.