Abstract:
A gas operating system for engaging the automatic or semi-automatic action of small arms. The system has a short, displaceable cylinder with a gas block ring secured thereto, a short, fixed piston attached coaxially to a gun barrel, and a single locking nut, advantageously in the form of a threaded flash suppressor. The piston includes gas block rings at its rearward exterior surfaces. The cylinder has a short stroke between radial forward and rear stops fixed on the barrel, which short stroke may be finely adjusted by threaded axial displacement of the rear stop. Pressurized combustion gas from fired ammunition fills a gas chamber formed by the interiors of the piston and cylinder, the gas entering through radial ports in the barrel. The system may be machined and assembled/disassembled with ease and may be readily adapted for employment in any small arms. The system may be fine tuned for usage with a wide spectrum of ammunition.

Description:
RELATED APPLICATION 
       [0001]    The present application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Appln. No. 62/019,974 filed Jul. 2, 2014, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Automatic and semi-automatic weapons have employed a variety of gas-operated systems utilizing the pressure of combustion gases released upon firing of a round to engage and displace a piston operatively associated with a bolt mechanism to unlock, extract, eject, feed, reload, lock and cock before firing the next round. Most of the prior art systems employ a piston-cylinder arrangement mounted parallel with the gun barrel, although U.S. Pat. No. 4,817,496 proposes utilizing the gun barrel itself as an in situ piston with large and small outer diameters being operatively associated with a sliding cylinder having corresponding large and small linear diameter portions mounted coaxially with and displaceable relative to the gun barrel. Such a system is subject to undue thermal expansion of the multi-diameter gun barrel negatively affecting operability and reliability. Moreover, such a system having a long stroke requires elaborate machining of the gun barrel outer surfaces and the cylinder for effecting the comparatively long stroke of the cylinder. 
         [0003]    There exists, therefore, a need to provide a novel system that overcomes the above-noted and other drawbacks of the existing systems. 
       SUMMARY OF THE PRESENT INVENTION 
       [0004]    The present invention is directed to a new and improved gas operating system for engaging the automatic or semi-automatic action of small arms. The new operating system in one aspect has essentially three fundamental components: a short, displaceable cylinder with a gas block ring secured thereto, a short, fixed piston attached coaxially to a gun barrel, and a single locking nut, advantageously in the form of a threaded flash suppressor. The piston includes gas block rings at its rearward exterior surfaces. The cylinder has a short stroke between radial forward and rear stops fixed on the barrel, which short stroke may be finely adjusted by threaded axial displacement of the rear stop. 
         [0005]    Pressurized combustion gas from fired ammunition fills a gas chamber formed by the interiors of the piston and cylinder, the gas entering through radial ports in the barrel. The new gas operating system may be machined and assembled/disassembled with great ease and may be readily adapted for employment in any small arms. The system may be fine tuned for usage with a wide spectrum of ammunition. 
         [0006]    In refined embodiments, either a manually adjustable valving mechanism or an automatic valving mechanism is associated with the piston to permit controlled escape of combustion gases through the forward piston wall to reduce the pressure in the gas chamber. 
         [0007]    The present invention in one aspect provides a gas operating system for engaging the automatic or semi-automatic action of a small arms weapon. The system comprises a gun barrel having a plurality of radial ports and having radial forward and rear stops fixed thereon. The system further comprises a displaceable cylinder with a gas ring block secured thereto, the cylinder having a short stroke between the radial forward and rear stops fixed on the gun barrel. The system further comprises a fixed piston attached coaxial to the gun barrel and having gas block sealing rings at rearward exterior surfaces of the piston. A gas chamber is formed by interior walls of the cylinder and piston and by outer surfaces of the gun barrel, wherein gas tightness of the gas chamber is established by the gas ring block of the cylinder and by the gas blocking sealing rings of the piston. The gas chamber receives in operation pressurized combustion gas from fired ammunition, the gas entering through the radial ports of the gun barrel. The system further comprises a single locking nut comprising a threaded flash suppressor, configured to lock the piston over the gun barrel. The rear stop is cylindrical and is threaded axially to the gun barrel so that the rear stop is rotatable to finely adjust the short stroke of the cylinder. 
         [0008]    The present invention in another aspect provides a gas operating system for engaging the automatic or semi-automatic action of a small arms weapon. The system comprises a gun barrel having a plurality of radial ports. A fixed piston is mounted coaxial with and secured to the gun barrel, the piston having annular grooves formed on rearward outer walls of the piston and gas blocking sealing rings disposed in the annular grooves. A sliding cylinder is mounted telescopically on the piston, the cylinder having inner surfaces and an interior wall and being open at a forward end and closed by a rear wall. A gas chamber is formed in part by the interior wall of the cylinder and outer surfaces of the gun barrel and further by the inner surfaces and a rear wall of the cylinder. The ear wall of the cylinder has a circular opening supporting a gas sealing ring of the cylinder which slidingly and sealingly engages the outer surfaces of the gun barrel, wherein gas tightness of the gas chamber is established by the gas sealing ring of the cylinder and by the gas blocking sealing rings of the piston. The gas chamber is being configured to, in operation, receive from the gun barrel pressurized combustion gas from fired ammunition, the gas entering through the radial ports of the gun barrel, the gas acting against the cylinder to effect rearward movement of the cylinder with respect to the piston. A bolt carrier  40  freely engages the rear wall of the cylinder and is configured to be engaged by the rearward movement of the cylinder to start the action of the weapon. The bolt carrier is forward biased and in operation urges the cylinder back to its forwardmost position, thereby expelling gas from the gas chamber back through the radial ports and out the gun barrel. 
         [0009]    The present invention in another aspect provides a gas operating system for engaging the automatic or semi-automatic action of a small arms weapon. The system comprises a gun barrel having a plurality of radial ports and having radial forward and rear stops fixed thereon. The system further comprises a displaceable cylinder with a gas ring block secured thereto, the cylinder having a short stroke between the radial forward and rear stops fixed on the gun barrel. A fixed piston is attached coaxial to the gun barrel and has gas block sealing rings at rearward exterior surfaces of the piston. A gas chamber is formed by interior walls of the cylinder and piston and by outer surfaces of the gun barrel. Gas tightness of the gas chamber is established by the gas ring block of the cylinder and by the gas blocking sealing rings of the piston. The gas chamber receives in operation pressurized combustion gas from fired ammunition, the gas entering through the radial ports of the gun barrel. The rear stop is cylindrical and is threaded axially to the gun barrel so that the rear stop is rotatable to finely adjust the short stroke of the displaceable cylinder. 
         [0010]    For a more complete understanding of the operation of gas operating system of the invention and a better appreciation of its attendant advantages, reference should be made to the following detailed description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an exploded perspective view of the fundamental elements of the gas operating system of the invention according to one embodiment; 
           [0012]      FIG. 2  is a perspective view of the piston and a cylinder, in mid-stroke position, and a locking element assembled with a gun barrel; 
           [0013]      FIG. 3  is a cross-sectional view of the gas operating system with the cylinder in its forwardmost position; 
           [0014]      FIG. 4  is an enlarged perspective view of the piston schematically showing the locations of gas sealing rings which are incorporated into the outer surfaces of the piston and in the rear wall of the sliding cylinder. 
           [0015]      FIGS. 5 and 5A  are exploded perspective views of an alternate preferred embodiment of the invention including a valving system; 
           [0016]      FIG. 6  is a perspective view showing the valving system of  FIG. 5  “closed;” 
           [0017]      FIG. 7  is a perspective view showing the valving system of  FIG. 5  “open;” 
           [0018]      FIG. 8  is an exploded perspective view of another alternate preferred valving arrangement; 
           [0019]      FIG. 9  is a front perspective view of the valve member shown in  FIG. 8 ; 
           [0020]      FIG. 10  is a rear perspective view of the valve member shown in  FIG. 8 ; 
           [0021]      FIG. 11  is a front cut-out view of the spring biased valve in closed position; 
           [0022]      FIG. 11A  is a perspective view of the spring biased valve in closed position; 
           [0023]      FIG. 11B  is a cross-sectional view of the spring biased valve in closed position; 
           [0024]      FIG. 12  is a front cut-out view of the spring biased valve in open position; 
           [0025]      FIG. 12A  is a perspective view of the spring biased valve in open position; 
           [0026]      FIG. 12B  is a cross-sectional view of the spring biased valve in open position; 
           [0027]      FIG. 13  shows the barrel with the suppressor installed and the valve pushed back by the suppressor; and 
           [0028]      FIGS. 14A and 14B  show the present invention without and with a suppressor, respectively. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    Referring now to  FIGS. 1 and 2 , the new gas operating system includes a piston element  10  mounted coaxially with and secured to a gun barrel  11  with a sliding cylinder  12  mounted telescopically on the piston for limited axial movement with respect thereto. The piston element  10  has a forwardly projecting collar  14  with an annular stop disc  13  at its outer forward end. Sealing rings  30  ( FIG. 4 ) are mounted in annular grooves  31  of the piston  10 . A gas chamber  17  ( FIG. 2 ) is defined in part by inner cylindrical piston wall  9  and outer barrel surfaces  11 . As can be seen in  FIG. 2 , the cylinder  12  slides over the piston  10  and over the barrel  11 . A flash hider  7  is used also to tighten the piston  10  against the barrel  11   
         [0030]    The cylinder  12  is open at its forward end and is closed by a rear wall  18  which has a circular opening  19  supporting a gas sealing ring  20  ( FIGS. 3 and 4 ) which slidingly, sealingly engages the outer surfaces  11  of the gun barrel. The inner surfaces  8  and rear wall  18  of the cylinder  11  complete the gas chamber  17  as will be understood. The sealing rings  30  and  20  maintain gas tightness of the chamber  17  and provide bearing surfaces for the cylinder to reciprocate over the piston  10  and gun barrel  11 . 
         [0031]    Specifically, the piston element  10  includes a shoulder  21  which engages a shoulder  22  formed on the outer barrel surface. In accordance with the invention, the piston element may be slipped over the barrel  11  until the shoulders  21  and  22  are engaged and then may be locked in place by threading a locking nut member  23 , advantageously in the form of a flash suppressor having internal threads  24 , over the threaded end  25  of the gun barrel  11 . This permits simple and rapid assembly and disassembly in accordance with the principles of the invention. Alternatively, the piston element  10  itself may be directly threadedly fastened to the barrel  11  eliminating the lock nut member. 
         [0032]    The gun barrel has a series of radial ports  26  communicating with chamber  17  which permit combustion gases under pressure to leave the bore of the barrel  11  and fill the gas chamber  17  to act against the cylinder to displace it rearwardly with respect to the piston  10 . The number and dimensions of the ports  26  may be varied for different power ammunition. The rearward movement of the cylinder will engage the bolt carrier  40  to start the “action” of the weapon. 
         [0033]    The forward travel of the cylinder  12  is limited by the stop disc  15 ; the rearward travel of the cylinder  12  is limited by a cylindrical rear stop  27  secured by interior threads  28  to mating threads  29  on the barrel. Thus, the total length of the cylinder displacement or cylinder stroke may be precisely adjusted to lengthen or shorten it by rotatingly threading the rear stop  27  along the barrel. 
         [0034]    In accordance with the invention, gas blocking sealing rings  30  are disposed in annular retaining channels  31  formed on the outer walls of the piston  12  ( FIG. 4 ). The rings  30  establish the gas tightness of the dynamic gas chamber  17  formed by the cooperation of the sliding cylinder  12  and the fixed piston  10 . Advantageously the sealing rings  30  may be of different, harder grade steel than that of the piston and cylinder, e.g., 17/7 stainless steel for the rings and 416 stainless steel for the piston and cylinder. 
         [0035]    In operation, a small arms weapon incorporating the new gas operating system will include a bolt carrier mechanism  40  having an arm element freely engaging the rear wall  18  of the cylinder without mechanical fastening thereto. Typically, the bolt carrier  40  will be forwardly biased by springs (not shown) to urge the cylinder  12  into its forwardmost position shown in  FIG. 3  after a trigger squeeze fires a round. At this stage, the projectile separated from the cartridge by combustion gas will leave the barrel and the pressurized combustion gases will enter the chamber  17  acting against the cylinder  12  to force it rearwardly moving the bolt carrier against its spring loading to effect the functions of unlocking and ejecting the spent cartridge and then chambering a fresh round while cocking the firing mechanism (the “action” which may be automatic or semi-automatic.) The next trigger squeeze or continuing the squeeze starts the firing cycle over as will be understood. 
         [0036]    In each cycle, excess combustion gas is expelled from the gas chamber  17  and back through ports  26  and out the barrel  11  when the cylinder  12  reciprocates forwardly under spring bias from the bolt carrier. This provides self-cleaning and eliminates carbon powder build-up. 
         [0037]    In instances where the nature of the ammunition employed creates undue pressure in the gas chamber  17 , a simple manual valving arrangement for the piston  10  may be incorporated. Relief of pressure is provided by ventilation ports  50  formed in the piston forward wall and selectively closeable by stopper surfaces  51  on arms  52  of an associated rotatable collar  53  supported in slots  54  (e.g., semi-circular or some other suitable configuration) formed in the front stop disc  13 . This valving arrangement is shown in  FIGS. 5 and 5A  where the threaded locking nut member  23 ( a ) fixes the piston  10  to the forward end of the barrel  11  in the manner described hereinabove and shown in  FIGS. 2 and 3 . 
         [0038]    As shown in  FIGS. 6 and 7 , the ventilation ports  50  may be selectively opened and closed to adjust and to control chamber pressure by manually rotating the collar  53  to move the arms into and out of ventilation port opening and closing positions. As shown in  FIG. 6 , with the valve in the “close” position, no gas will come out from the piston  10  during the firing. As shown in  FIG. 7 , with the valve in the “open” position, part of the gas will go out from the piston  10 , reducing the internal pressure. The dimensions and number of ports  50  may be varied to correlate with pressures generated by different ammunition strength. Any known detenting mechanism may be included in this simple valving arrangement, if desired to provide a series of discrete positions. 
         [0039]    Alternatively to the manual rotatable valving arrangement of  FIGS. 5A ,  5 B,  6 , and  7 , a spring-biased two phase (open/closed) valving system shown in  FIGS. 8-14  may be advantageously employed. The spring-loaded valving system of this embodiment is designed to avoid the adjustments from the operator. 
         [0040]    As shown in  FIG. 8 , the piston  10  has radial ports  60  formed in a forwardly extending annular collar  61 . An associated cylindrical valve  70  is mounted for limited axial movement on the gun barrel with respect to the piston ports  60 . Specifically, the valve  70  has a rear cylindrical collar  71  which is normally biased forwardly by a biasing spring  80  into the valve “closed” position shown in  FIGS. 11A and 11B  with the collar surfaces or sealing surfaces  73  blocking the radial ports  60  in the piston. Venting channels  72  are formed forwardly of the collar  71 . The valve  70  itself is secured to the barrel by a snap ring  90 , to prevent the valve  70  from coming off the system. Thus, as shown in  FIGS. 11A and 11B , with the valve  70  in the “CLOSE” position, no gas will come out from the piston  10  during the firing; the sealing surface  73  will close the exit holes or radial ports  60  of the gas piston  10 . 
         [0041]    In accordance with this specific aspect of the invention, a suppressor  23 , such as the suppressor shown in  FIG. 1 , is threaded on to the barrel  11  to engage the valve  70  to displace it rearwardly into the “open” position shown in  FIG. 12 , thereby unblocking the ports  60  from the collar  71  and permitting communication to the atmosphere from the interior of the barrel  11  through the radial ports  26  in the barrel and through the radial ports  60  in the piston and through the venting channels  72 . As shown in  FIGS. 12A and 12B , with the suppressor  23  on, the valve  70  will be pushed back by the suppressor  23  (see the arrow in  FIG. 12A ) to the “OPEN” position, and part of the gas will go out from the valve  70  through the gas vent channels  72 .  FIG. 13  is a view similar to  FIG. 12B  only it shows the barrel  11  with the suppressor  23  installed; as can be seen by the arrow in the figure the valve  70  is pushed back by the suppressor  23 . In this alternative arrangement, no manual adjustment of the valve  70  by rotation or otherwise is required. It is normally closed when on the barrel  11  with the assembled biasing spring  80  and snap ring  90 . When the suppressor  23 , functioning as a simple locking nut, is threaded on to the barrel, it automatically overcomes the spring bias and opens valve  70  while completing the assembly of the gas operating system itself. 
         [0042]      FIGS. 14A and 14B  show the present invention of this embodiment without a suppressor ( FIG. 14A ) and with a suppressor ( FIG. 14B ). In this embodiment the gas will enter the system through the holes  26  on the barrel  11 . At this point without a suppressor ( FIG. 14A ), the gas will be entirely used to cycle the gun, since the valve holes  94  will be closed. With the suppressor  23  ( FIG. 14B ), the valve will be pushed back and then the valve holes  94  will be open. In such condition, part of the gas will be used to cycle the gun, another part will leave the gas system and will enter the suppressor  23  through the suppressor holes  96 , improving the performance of the suppressor  23  itself. In this way, the pressure inside the system will be reduced and the gun will cycle at a slower rate. It should be noted that the gas flow entering the system (the piston  10 ) is always the same. Thus, with the suppressor  23  the gas enters the suppressor  23  through the holes  94  on the valve, and it should be noted that the valve holes  94  do not reduce the gas flow; they simply allow part of the gas to exit the system. Thus, main components of this embodiment are the valve  70 , the spring  80 , and the snap ring  90 . The suppressor  23 , when installed, will directly push the valve  70 , which is responsible for the “opening” or for the “closing” of the holes. 
         [0043]    Accordingly, with respect to the present invention according to this embodiment, the valve is annular to the barrel. Gas is moved out of the system. Gas is moved from the gas block into the suppressor, to reduce the pressure inside the system and increase the performance of the suppressor. To the contrary, in some prior art systems, the intent is to reduce the flux of the gas that is going into the gas system. However, this could be problematic because it could cause the closing of the small hole of the mechanism due to the unburnt powder and, further, such a system may be highly complicated and difficult to machine. 
         [0044]    It will be appreciated that the operating system of the present invention provides many advantages and improvements over known gas piston operating systems. The new design is greatly simplified and especially streamlined, permitting ease of manufacture, cleaning, assembly and disassembly of the components of the system. One unthreading operation of the locking nut/suppressor permits disassembly. Only three parts need to be cleaned. The new design is easy to machine due to only turning operations and one machining operation on the three parts. The use of separate gas sealing rings on the piston and cylinder establishes a gas tight chamber for combustion gases to displace the cylinder while simplifying fabrication. Mounting the piston concentrically on the barrel effectively safely spaces the sliding cylinder from the barrel and eliminates detrimental effects of thermal expansion of the barrel. 
         [0045]    The overall design of the new operating system enables an effective mechanism having a short stroke to be reliably incorporated into a small envelope of a small arms barrel. This permits construction of compact and concealable weapons with powerful small caliber. The new design accommodates the inclusion of sufficient gas ports to fire extremely low pressure ammunition. Moreover, by increasing the diameter and number of barrel gas ports, contamination of the weapon is significantly reduced. 
         [0046]    The new system can be employed with weapons of widely disparate calibers. The length of the stroke may be adjusted along with sizing the ports and/or varying the number of ports to “fine tune” the operating system to the ammunition being fired in terms of bullet weights and generated gas pressures. The spring-biased valving provided in conjunction with the system is simple and efficient and permits further “fine tuning” of the gas operating system to particular caliber ammunition while having the ability to avoid manual adjustments. By virtue of the features of the present invention it is possible to avoid the manual adjustments of users that are often critical under a stressful operation in the field. The automatic biased valving may be employed in conventional gas operating systems as well as the new and improved annular system disclosed herein. 
         [0047]    It should be understood, of course, that the specific form of the invention herein illustrated and described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Thus, it should be understood that the embodiments herein have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein without departing from the spirit and scope of the present invention. Thus, the present invention should not be limited by any above-described exemplary embodiment. 
         [0048]    In addition, it should be understood that the figures illustrated in the attachments, which highlight the functionality and advantages of the present invention, are presented for example purposes only. The architecture of the present invention is sufficiently flexible and configurable, such that it may be utilized (and navigated) in ways other than that shown in the accompanying figures.