Abstract:
An adjustable pressure regulator controls the flow of a gas from a high pressure source to a low pressure device at a predetermined outlet pressure. The regulator includes a body, a piston assembly carried by the body. The assembly has a piston, a flow conduit formed in the piston and a biasing element operably connected to the piston. The flow conduit has a regulated pressure outlet end. The piston and flow conduit are movable longitudinally in the body. A retainer element is engageable with the body and is movable toward and away from the body and the piston. A seat is carried by the retainer element and is movable therewith. The seat is engaged by the flow conduit to isolate a flow path through the regulator and disengaged from the flow conduit to provide a flow path through the flow conduit. The piston assembly biasing element biases the flow conduit away from the seat to open a flow path through the regulator. Gas pressure on the piston urges the flow conduit into contact with the seat to close the flow path through the regulator. The retainer element and seat are movable toward and away from the body to vary a distance of movement of the flow conduit toward and away from the seat to vary the predetermined outlet pressure.

Description:
BACKGROUND OF THE INVENTION 
   The present invention is directed to a novel pressure regulator. More particularly, the present invention relates to a fine adjustment, adjustable pressure regulator for use in paint ball guns that use compressed gas to fire projectiles. The present invention is also adapted for use with other pressurized gas devices. 
   Sporting events that provide the participant with an adventure in military strategy and the feel of the fear and exhilaration of battle have become very popular. Generally participants are equipped with a gas projectile gun or rifle (which can launch a projectile without seriously harming the victim) and protective gear and are divided into two or more combat groups each with the goal of surviving the others. 
   One such sporting event is commonly referred to as “paintball”. In this event, participants fire paint-filled projectile balls at one another. In a typical paintball event, participants fire projectiles, or paintballs, at one another and, when struck, are “painted” by the paint ball. The objective of such an event is to be the last person that has not been “painted” or hit with a projectile. 
   Typically, the projectiles used in these events are propelled, generally using a compressed gas to avoid the potential dangers of explosives such as gun powder. The dangers of explosives include not only the physical danger of the explosion but also the increased speed that such explosions impart to projectiles, potentially making innocuous projectiles, such as paintballs, deadly. Moreover, compressed gas is less costly than explosives and is readily obtainable. 
   When these types of systems are used, compressed gas is provided or supplied from a high-pressure source carried by the participant in a gas bottle. Although high-pressure gas is needed at the gun firing mechanism to propel the paint balls, typically the pressure in these bottles is greater than the pressure needed to safely propel the projectile within the parameters of the game. As such, it is necessary to regulate the pressure of the compressed gas provided to the gun firing mechanism to allow projectiles to be launched at a safer velocity and prevent damage to the gun. Typically, a regulator is provided, mounted to the gun or the compressed gas bottle. That is, it is carried by the game participant. 
   Known pressure regulator can be quite large and as such can add considerable weight to the gun. In that one of the objectives of paint ball is to avoid one&#39;s opponent, any added weight is undesirable. 
   Moreover, although many such regulators in fact function well to regulate and reduce pressure from the bottle to the firing mechanism, often such pressure regulation or reduction is rough. That is, the outlet pressure is typically within a range that is specified for the particular gun. However, there remains an “optimum” pressure for the mechanism to operate. 
   Accordingly, there exists a need for a pressure regulator that can be easily adjusted to provide a downstream or outlet pressure. Desirably, such a regulator is sufficiently small and light-weight so that it does not increase, to any extent, the weight carried by a participant in a paint ball sporting event. More desirably such a regulator provides a precisely controlled “fine-tuned” downstream pressure that can be set for optimum gun performance. 
   BRIEF SUMMARY OF THE INVENTION 
   An adjustable, fine adjustment gas regulator is configured to provide a precisely controlled downstream pressure that is regulated, essentially regardless of the upstream pressure. The regulator is used to control the flow of a gas from a high pressure source to a low pressure device. The gas is delivered from the regulator at a predetermined outlet pressure. 
   The regulator includes a body. A piston assembly is carried by the body. The assembly has a piston, a flow conduit formed in the piston and a biasing element, preferably a coil spring, operably connected to the piston. The flow conduit has a regulated pressure outlet end. The piston and flow conduit are movable longitudinally in the body. 
   A retainer element is engageable with the body and movable is toward and away from the body and the piston. A seat is carried by the retainer element and is movable with the retainer element. The seat is engaged by the flow conduit to isolate a flow path through the regulator and disengaged from the flow conduit to provide a flow path through the flow conduit. The regulator includes an inlet in flow communication with the retainer element. 
   The piston assembly biasing element biases the flow conduit away from the seat to open a flow path through the regulator. Gas pressure on the piston urges the flow conduit into contact with the seat to close the flow path through the regulator. The outlet pressure is varied or adjusted by moving the retainer element and seat toward and away from the body. This varies the distance of movement of the flow conduit toward and away from the seat thus varying the outlet pressure. 
   To provide the adjustment, the pressure regulator includes an adjusting collar operably connected (preferably threaded) to the body and operably connected to the retainer element and seat. As the collar threads onto and off of the body, it moves the retaining element and the seat toward and away from the flow conduit. 
   The regulator includes an inner shaft, a seal retainer and a retaining block that all move with the adjusting collar toward and away from the piston. This assembly supports the seat and provides gas passages through the regulator. A high pressure gas clearance is defined between the inner shaft and the seal retainer and a gas path is defined from the inlet to the high pressure gas clearance and from the high pressure gas clearance to the to the seat and flow conduit. 
   These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein: 
       FIG. 1  is a cross-sectional view of a fine adjustment gas regulator embodying the principles of the present invention; 
       FIG. 2  is an exploded view of the gas regulator of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view of the gas regulator as it is set for a lower downstream or outlet pressure; 
       FIG. 4  is a cross-sectional view of the gas regulator (showing a view similar to FIG.  3 ), in which the regulator is set for a higher downstream or outlet pressure; 
       FIG. 5  is a cross-sectional view of the main body of the regulator; 
       FIG. 6  is a cross-sectional view of the adjusting collar; 
       FIG. 7  is a cross-sectional view of the retaining block; 
       FIG. 8  is a cross-sectional view of the inner shaft; and 
       FIG. 9  is a cross-sectional view of the seal retainer. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated. 
   It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein. 
   Referring now to the figures, and in particular to  FIG. 1 , a present regulator  10  is configured to provide a precisely controlled downstream pressure that is regulated, essentially regardless of the upstream pressure. The regulator  10  includes generally, a main body  12 , a piston assembly  14  disposed within the body  12 , an adjusting collar  16  that is rotatable relative to the body  12  (to provide the downstream pressure adjustment), a trim or nose piece  18 , and an inner shaft or inner tube  20  that extends from the main body  12  to the trim piece  18 . A seal retainer  22  is disposed in the main body  12 , between the main body  12  and the inner shaft  20 . 
   Gas flow is into the regulator  10  is (as indicated by the arrow at  24 ), into the inner shaft  20  at the trim piece  18 . Gas flows out of the regulator  10  through the piston assembly  14 , as at the main body  12 . To this end, the inner shaft  20  or inlet end may be referred to as “upstream” or an upstream end, whereas the main body  12  end, at the outlet at the piston assembly  14  may be referred to as “downstream” or a downstream end. 
   Referring now to  FIGS. 1 and 5 , the main body  12  includes a male threaded downstream end  26  to which the regulator  10  is mounted, for example, to an air gun receiver (not shown). The main body  12  defines a piston cavity  28  (in the downstream end), and a seal retainer cavity  30  at an upstream end, that are separated from one another by a pocket wall  32 . The pocket wall  32  has an opening  34  therethrough. 
   As seen in  FIGS. 1 and 2 , the piston assembly  14  is positioned within the piston cavity  28 . The piston assembly  14  includes a piston  36  that extends across the cavity  28 , a flow conduit or tube  38  fixedly mounted to the piston  36  (as by brazing), and a biasing element, such as the illustrated coil spring  40 , disposed about the tube  38 , between the piston  36  and the piston cavity pocket floor  42 . Those skilled in the at will recognize that the biasing feature can be provided by various other elements, such as spring washers and the like. 
   The tube  38 , which is hollow, is positioned in and extends through the opening  34  in the pocket floor  42  and extends into the piston  36  thus providing a gas passage through the piston  36 . The tube  38  can have a beveled edge  39 . A seal, such as the exemplary O-ring  44  is positioned on the piston  36  to seal the piston cavity  28  from the environs. A spring clip or the like (not shown) is positioned in a channel  46  in an inner surface of the piston cavity  28  so that the action of the spring  40  does not force the piston assembly  14  out of the cavity  28 . That is, the clip retains the piston assembly  14  within the cavity  28 . 
   The main body  12  further includes an externally threaded upstream end  48  and a step or shoulder  50  in the body  12  intermediate the (threaded) upstream end  48  and the downstream end  26 . A plurality of recesses  52  are longitudinally formed in the main body  12 , circumferentially disposed about the body  12 , between the threaded upstream end  48  and the shoulder  50 . 
   The main body  12  is configured for engagement with the adjusting collar  16 , best seen in FIG.  6 . The adjusting collar  16  includes a cavity  54  having an internal thread  56  for mating with the external upstream end  48  threads of the main body  12 . An internally formed step  58  in the collar  16 , spaced from the threads  56 , is configured for engagement with the main body shoulder  50  to provide a limit for threading the main body  12  into the collar  16 . A transverse threaded opening  60  is formed in the collar  16  for receiving a set screw or other adjustment securing element (not shown). At an upstream end of the collar, an internal, inwardly extending stop wall  62  is formed. 
   Referring to  FIGS. 5 and 9 , the seal retainer  22  is positioned in the main body seal retainer cavity  30 . The seal retainer  22  is an elongated cup-shaped element that includes an opening  64  in a base portion  66  of the element for receiving the piston assembly flow tube  38 . The seal retainer  22  is configured to retain or support the pressure reducing components. To this end, the seal retainer  22  includes a well  68  at the downstream end (adjacent the base  66 ) within which the opening  64  is formed. A lip  70  extends inwardly to define the well  68 . 
   A retaining block  72 , illustrated in  FIG. 7  is disposed within the seal retainer well  68  and a seal, such as the illustrated O-ring  74  is positioned within the well  68 , to form a seal at the well opening  64 /flow tube  38 /retaining block  72  interface. The retaining block  72  has a step-like shape and sits on a mating shoulder  76  of the seal retainer well  68 . The retaining block  72  defines a plurality of gas passages  78  therethrough. The seal retainer  22  includes an internal thread  80  at the upstream end. 
   The inner shaft  20 , best seen in  FIG. 8 , includes an external thread  82  and matingly threads with the seal retainer  22 . The inner shaft  20  has an inner bored-out region  84  and terminates at a sealed end  86 . A plurality of gas passages  88  extend between the inner bored-out region  84  and an external portion of the shaft  20 . In that the seal retainer  22  and the inner shaft  20  are threadedly engaged with one another, they function as a single, unitary element. That is, as will be described below, they move with one another, relative to the regulator main body  12 . A space between the shaft  20  and seal retainer  22  defines a high pressure gas clearance  90  (FIG.  1 ). 
   A seal or seat  92  is positioned within the seal retainer  22 , on the retaining block  72 . The seat  92  is disposed at a downstream end  98  of the inner shaft  20 . The seat  92  is configured as a stop block for the flow tube  38  to bear against to initiate and terminate gas flow through the regulator  10 . In a present regulator  10 , the seat  92  is formed from a resilient material, such as neoprene. The inner shaft  20  further includes an internally threaded inlet or upstream end  94  and a set wall  96  extending outwardly intermediate the upstream  94  and downstream  98  ends thereof. To assure a gas tight seal between the inner shaft  20  and the seal retainer  22 , a seal, such as the exemplary O-ring  100  is disposed at the upstream or high pressure end  94  of the threaded interface. 
   The trim piece or nose piece  18  is fitted onto the upstream end  94  of the inner shaft  20  externally thereof. In a present regulator  10 , the trim piece  18  is press fitted onto the inner shaft  20  so that the trim piece  18  and shaft  20  (like the inner shaft  20  and seal retainer  22 ) function as a single unitary element. 
   In operation, gas enters the upstream end  94  of the inner shaft  20  and flows through the regulator as indicated by the flow arrows at  24 . The gas flows into the inner shaft bored-out region  84  and through the gas ports  88 , into the gas clearance  90 . The gas then flows from the clearance  90  through the gas ports  78  in the retaining blocks  72 . If, as seen in  FIGS. 1 and 2 , the flow tube  38  is bearing against the seat  92 , the flow of gas is stopped at the flow tube  38 /seat  92  interface. When, however, the tube  38  is spaced from the seat  92  (as the piston  36  is urged outwardly by the spring  40  force), gas flows into the space between the tube  38  and seat  92 , and flows out of the tube  38  at the downstream or piston end  102 . 
   The seating and unseating of the tube  38  on the seat  92  is determined by the downstream pressure, that is, the pressure exerted by downstream gas on the piston  36 . As seen in  FIG. 2 , which shows the tube  38  seated on the seat  92  (and thus downstream isolation), the downstream pressure is sufficiently high at the piston  36  to overcome the spring  40  force. That is, the gas pressure on the piston  36  is sufficiently high to urge the piston  36  (in the direction as indicated by the arrow at  104 ) to seal the flow passage through the tube  38 . As the downstream pressure begins to drop, the force of (or pressure induced by) the gas on the piston  36  is commensurately reduced. The spring  40  force thus overcomes the gas pressure force, which in turn urges the piston (in the direction indicated by the arrow at  106 ) to open the regulator  10 . This moves the tube  38  from (i.e., off of ) the seat  92 , permitting gas flow through the regulator  10 . Once the downstream pressure has increased sufficiently, the regulator cycles and the spring  40  force is overcome (by the gas force induced on the piston  36 ), and the tube  38  begins to seat, again isolating regulator  10  flow. 
   The downstream or outlet pressure is readily set by varying the amount of movement of the spring  40  that is required to isolate the outlet side flow. That is, by increasing the distance that the spring  40  is required to move the tube  38  to seat on the seat  92 , the outlet pressure can be increased. Conversely, by decreasing the amount of spring  40  travel, the tube  38  seats “earlier” in the travel, thus reducing the downstream pressure. 
   The relative required movement of the spring  40  is readily accomplished by adjusting the adjusting collar  16  relative to the main body  12 . As set forth above, the inner shaft  20  and the seal retainer  22  are fixedly mounted to one another by a threaded mounting  80 / 82 . Likewise, the inner shaft  20  and trim piece  18  are fixedly mounted to one another by the press fit of the trim piece  18  onto the inner shaft  20 . Thus, the trim piece  18 , inner shaft  20  and seal retainer  22  all move together as a single unitary element. 
   The adjusting collar  16  moves longitudinally along with the trim piece  18 /shaft  20 /seal retainer  22  element. This is assured by the clearance fit of the adjusting collar  16  between the trim piece  18  end and the shaft set wall  96 . And, longitudinal movement of the trim piece  18 /shaft  20 /seal retainer  22  element is effected by rotating the adjusting collar  16  relative to the main body  12  (about their respective mating threads  48 / 56 ). 
   Referring to  FIGS. 3 and 4 , the regulator  10  is shown set for a low or minimum outlet pressure ( FIG. 3 ) and for a high or maximum outlet pressure (FIG.  4 ). A comparison of these figures shows that at a minimum outlet pressure, the seal retainer  22  is fully seated in the main body seal retainer cavity  30 . In this manner, the spring  40  is at a lesser compressed state to seat the tube  38  on the seat  92 . At this setting, less pressure is required on the piston  36  to (compress the spring  40 ) to move the piston assembly  14  to seat the tube  38  on the seat  92 . 
   Conversely, as seen in  FIG. 4 , when the regulator  10  is adjusted to move the trim piece  18 /shaft  20 /seal retainer  22  element away from the “bottom” of the seal retainer cavity  30  (see gap at  108 ), the spring  40  is required to move (compress) a greater distance to seat the tube  38  on the seat  92 . As such, a greater pressure is required on the piston  36  to overcome the spring  40  force and to move (or seat) the tube  38 . 
   As set forth above, once the regulator  10  is “set” for a desired outlet pressure, it can be locked into position. In a present regulator  10 , once a desired outlet pressure is achieved, the set screw (not shown) is threaded into the adjusting collar set screw opening  60 . This seats the set screw into one of the longitudinal recesses  52  in the main body  12 , thus preventing rotation of the adjusting collar  16  relative to the main body  12 . 
   In a present regulator  10 , the seat  92  and the various seals (or O-rings)  44 ,  74 ,  100  are formed from a resilient, polymeric material, such as neoprene and the like. The various pressure retaining and structural elements are formed from metals, such as steel, aluminum and the like. Those skilled in the art will recognize other materials from which the regulator  10  and components can be formed. 
   All patents referred to herein, are hereby incorporated herein by reference, whether or not specifically done so within the text of this disclosure. 
   In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular. 
   From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.