Patent Publication Number: US-10330419-B1

Title: Firearm sound suppressor

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates in general to firearms, and in particular to sound suppressors for firearms. 
     BACKGROUND OF THE INVENTION 
     Sound suppressors for firearms have been used for over a century to reduce the sound of muzzle blasts from firearms by impeding the rapid release of gases produced by ignited bullet propellant. Sound suppressors often have a plurality of baffles which are directly connected to one or more gas expansion chambers. The gas expansion chambers may be integral with or part of baffle components. Some firearms have integrated sound suppressors in which the barrel has multiple ports extending down the length of the barrel which are connected to one or more expansion chambers. 
     Prior art sound suppressors have also included wipers formed of soft materials which are mounted to extend across the bore of a suppressor and either have perforations which conform closely to the gauge of the round being fired or which are perforated by the first round being fired through a suppressor. Wipers provide a gas check feature to assure that propellant gases do not exit a firearm suppressor prior to the projectile exiting the suppressor. These type of wipers were lower cost and did not require precision machining. Wipers formed of soft material will typically have to be replaced after a few rounds are fired. 
     SUMMARY OF THE INVENTION 
     A firearm sound suppressor is disclosed having a muzzle cap, a baffle tube, an exterior tube, an end cap, and a plurality of baffles. The muzzle cap is configured for mounting to the muzzle of a gun barrel for a firearm. The baffle tube and the exterior tube are concentrically disposed with the baffle tube interiorly disposed within the exterior tube and an expansion chamber defined in the space there-between. The expansion chamber is a single chamber which runs the entire length of the suppressor. The muzzle cap connects to the rearward ends of the baffle tube and the exterior tube and encloses a first end of the expansion chamber, with a rearward end of the muzzle cap secured to the exterior tube and a forward end of the muzzle cap secured to the baffle tube. The forward end of the muzzle cap is spaced apart from the rearward end of the muzzle cap with a cage-like structure extending there-between to define a plurality of flow ports of elongate shape, extending from an interior of the muzzle cap to an exterior of the muzzle cap and providing fluid communication between the muzzle of the firearm and the expansion chamber. Preferably, the vent ports extend along a longitudinal length of the suppressor and are no longer than the length of a bullet being used, but may be longer. The vent ports are located adjacent the muzzle of the barrel and are fully open, that is, without obstruction, to allow for rapid and full utilization of the expansion chamber. 
     The end cap is mounted to forward ends of the exterior tube and the baffle tube, enclosing a second end of the expansion chamber. The end cap has a centrally disposed bullet port which is aligned with the gun barrel, the muzzle cap, and the baffle tube. Vent ports extend through the end cap disposed circumferentially around the bullet port, with the vent ports extending between the expansion chamber to an exterior of the suppressor for providing fluid communication there-between. The vent ports are of a size for restricting flow of propellant gases from the expansion chamber to the exterior of the suppressor, and for providing pressure relief when high pressures are encountered in the expansion chamber. The vent ports provide pressure relief, but restrict flow there-through and are not the primary means of evacuating propellent gases from the expansion chamber. The primary means of evacuating propellant gases from the expansion chamber is through the central bore of the suppressor, either through the baffles when used or through the baffle tube when baffles are not utilized in the suppressor, as noted below. 
     The plurality of baffles are tubular shaped and fit into the interior bore of the baffle tube to provide a baffle stack, which defines a central bore of the suppressor. The baffles are press fit into the baffle tube in a preferred embodiment, and in other embodiments the baffles may freely slide into the baffle tube. The baffles have sidewalls with continuous inner surfaces, that is, surfaces which are imperforate, without openings such that the sidewalls of the baffles seal between the central bore of the baffles and the baffle tube. Each of the baffles has a circumferentially extending upset which is an interiorly disposed protuberance provided by an annular-shaped tab extending radially inward. The upset or protuberance is located in a forward end of the respective baffles and provides a gas check. In some embodiments the baffles may be omitted and then the baffle tube sized in close tolerance to the bullet being used to provide the gas check feature. The gas check feature prevents spent propellant gases from moving outward of the suppressor prior to the bullet being fired, such that most of the propellant gases pass into and build pressure within the entire volume of expansion chamber. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying Drawings in which  FIGS. 1 through 12  show various aspects for a firearm sound suppressor made according to the present invention, as set forth below: 
         FIG. 1  is a perspective view of a firearm sound suppressor made according to the present invention; 
         FIG. 2  is an exploded view of the sound suppressor; 
         FIG. 3  is a longitudinal section view of the sound suppressor of  FIG. 1  taken along section line  3 - 3 ; 
         FIG. 4  is a longitudinal section view of an exterior tube of the sound suppressor; 
         FIG. 5  is a longitudinal section view of a baffle tube of the sound suppressor; 
         FIG. 6  is a side view of a muzzle cap of the sound suppressor; 
         FIG. 7  is a sectional view of the muzzle cap taken along section line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a left side view of an end cap of the sound suppressor; 
         FIG. 9  is a sectional view of the end cap taken along section line  9 - 9  of  FIG. 8 ; 
         FIG. 10  is a sectional view of a baffle section for use in the sound suppressor of  FIGS. 1-3 ; 
         FIG. 11  is a longitudinal section view of an alternative sound suppressor as would be viewed if taken along section line  3 - 3  of  FIG. 1 , showing the alternative sound suppressor as having an alternative baffle tube; and 
         FIG. 12  is a longitudinal section view of the alternative baffle tube of the sound suppressor of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view of a firearm suppressor  12 , and  FIG. 2  is an exploded view of the firearm suppressor  12 . The suppressor  12  has an exterior tube  14  running the full length thereof A muzzle cap  16  is disposed in a first end  32  of the exterior tube  14 . An end cap  18  is disposed in a second end  42  of the exterior tube  14 . A baffle tube  20  is provided which extends from the muzzle cap  16  to the end cap  18 . A plurality of baffles  22  are provided for stacking within the baffle tube  20 . In the present embodiment there are sixteen of the baffles  22  which are press fit into the baffle tube  20  to provide a columnar baffle stack  66  (shown in  FIG. 3 ). The muzzle cap  16  has threads  24  which engage with interior threads  28  on the first end  32  of the exterior tube  14 . The end cap  18  has exterior threads  26  which are provided for engaging with the interior threads  30  on the second end  42  of the exterior tube  14 . The muzzle cap  16  has a cage-like structure  34  having a plurality of flow ports  36  of elongate shape. The flow ports  36  extend radially around the exterior of the cage-like structure  34 . A terminal end of the muzzle cap  16  has a socket  38  for receiving a first end  40  of the baffle tube  20 . The end cap  18  has a body with a disk-like shape  44 , and a bullet port  46  which is preferably a squared shape extending there-through. A plurality of vent ports  48  extend circumferentially around the bullet port  46 . A rearward end of the end cap  18  has a socket  50  for receiving a second end  52  of the baffle tube  20 . 
       FIG. 3  is a longitudinal section view of the suppressor  12 , taken along section line  3 - 3  of  FIG. 1 . An expansion chamber  56  is defined by an annular-shaped space  56  extending between the exterior tube  14  and the baffle tube  20 , having a length extending from the muzzle cap  16  to the end cap  18 . The expansion chamber  56  is a single chamber which runs the entire length of the suppressor  12 , unobstructed for the entire length thereof. The flow ports  36  in the muzzle cap  16  provide fluid communication between the expansion chamber  56  and a central bore  54  of the suppressor  12  and the muzzle of a gun barrel to which the suppressor  12  is mounted. The flow ports  36  are disposed in the first end of the suppressor  12  which mounts directly to the barrel of a firearm, and the central bore  54  of the suppressor  12  is only connected to the expansion chamber  56  through the vent ports  36  located in the first end of the suppressor  12 . Preferably, the flow ports  36  extend along a longitudinal length of the suppressor  12  for no longer than the length of a bullet being used, but may be longer. The flow ports  36  are located adjacent the muzzle of the barrel and are fully open, without obstruction, to allow for rapid and full utilization of the expansion chamber  56 . 
     The baffle tube  20  has a sidewall  86  which is imperforate, being continuous and not having any ports extending through the sidewall  86  of the baffle tube  20  to connect the interior of the baffle tube  20  with the expansion chamber  56 . The propellant gases only pass through flow ports  36  in the muzzle cap  16 , and not through any portion of the sidewall  86  of the baffle tube  20 . A longitudinal axis  58  extends centrally through the suppressor  12 , co-axial with the exterior tube  14 , the muzzle cap  16 , the end cap  18 , the baffle tube  20 , and the baffles  22 . An annular-shaped groove  64  is provided in the rearward face of the end cap  18 , in fluid communication with the expansion chamber  56 . The plurality of baffles  22  are stacked end-to-end within the interior of the baffle tube  20  to define a baffle stack  66 . There are preferably sixteen baffles in the present embodiment. Preferably the baffles  22  are press fit into the interior surface of the baffle tube  20 . In some embodiments, as shown in  FIGS. 11 and 12 , the baffles  22  which were included in the interior bore  84  of the baffle tube  20  may be omitted may be omitted and an alternative baffle tube  88  used, instead of the baffle tube  20 . The alternative baffle tube  88  is sized with an inner bore  96  to both freely pass a bullet passing through the suppressor  12  and provide a gas check feature in which propellant gases are prevented from flowing past the bullet being fired through the suppressor  12 , such that most of the propellant gases are forced to pass through the vent ports  36  and into the expansion chamber  56 . 
       FIG. 4  is a longitudinal section view of the exterior tube  14  of the sound suppressor  12 . The exterior tube  14  has sidewall which is preferably coaxial with the longitudinal axis  58  and an interior bore  82 . Threads  28  are formed into the interior of the exterior tube  14  at the first end  32 , and threads  30  are formed into the interior of the exterior tube  14  at the second end  42 . The exterior tube  14  has a tubular body which is preferably imperforate, such that sidewalls thereof are continuous and without perforations or other openings through which propellant gases could flow. 
       FIG. 5  is a longitudinal section view of a baffle tube  20  of the sound suppressor  12 . The baffle tube  20  has a rearward end defined by a first end  40  and a forward end defined by a second end  52 . Preferably the first end  40  and the second end  52  are of uniform shape, not having threads nor reduced diameters. The baffle tube  20  has a tubular body with a sidewall  86  which is imperforate, that is, the sidewall  86  is continuous since it is without perforations or other openings through which propellant gases could flow and without upsets. The baffle tube  20  has an interior bore  84  which in other embodiments in which baffles  22  are not used will be sized to provide a gas check feature, and then will provide the central bore  54  for the suppressor  12  through which bullets pass. 
       FIG. 6  is a side view of a muzzle cap  16  and  FIG. 7  is a sectional view of the muzzle cap  16 , taken along section line  7 - 7  of  FIG. 6 . The muzzle cap  16  has threads  24  which are provided for engaging with interior threads  28  on the first end  32  of the exterior tube  14 . The muzzle cap  16  has a cage-like structure  34  having a plurality of vent ports  36  of elongate shape. The vent ports  36  extend radially around the exterior of the cage-like structure  34 , defining, or providing, openings which preferably extend about the longitudinal axis  58  at an angle  60  of approximately sixty degrees. The vent ports  36  are spaced apart by metal ribs defining the cage-like structure  34  which preferably extend for an angle  62  of approximately thirty degrees around the longitudinal axis  58 . A terminal end of the muzzle cap  16  has a socket  38  for receiving a first end  40  of the baffle tube  20 . 
       FIG. 8  is a left side view of an end cap  18  and  FIG. 9  is a sectional view of the end cap  18 , taken along section line  9 - 9  of  FIG. 8 . The end cap  18  has a body with a disk-like shape  44 , and a bullet port  46  which is preferably a squared shape extending there-through. A rearward end of the end cap  18  has a socket  50  for receiving a second end  52  of the baffle tube  20 . The end cap  18  has exterior threads  26  which are provided for engaging with the interior threads  30  on the second end  42  of the exterior tube  14 . A plurality of the vent ports  48  extend circumferentially around the bullet port  46 . The vent ports  48  provide pressure relief ports which are sized for restricting flow of propellant gases from the expansion chamber  56  to the exterior of the suppressor  12 , and for providing pressure relief when high pressures are encountered in the expansion chamber  56 . The vent ports  48  are not the primary means of evacuating propellent gases from the expansion chamber  56 . The primary means of evacuating propellant gases from the expansion chamber is through the central bore  54  of the suppressor  12 , either through the interior bore  54  of the baffles  22  as in the present embodiment, or in other embodiments, such as shown in  FIGS. 11 and 12 , through an appropriately sized inner bore  96  of the alternative baffle tube  88  when the baffles  22  are not utilized in the suppressor  12  and the inner bore  96  of the alternative baffle tube  88  then provides the central bore for the suppressor  12 . 
       FIG. 10  is a longitudinal section view of one of the baffles  22 , taken along section line  3 - 3  of  FIG. 1 . The baffle  22  has a tubular body  70  which is preferably of a uniform cylindrical shape having a central bore  54  and an inwardly extending protuberance provided by an upset  78 . The upset  78  is preferably an annular-shaped tab which extends inward at the forward end of the tubular body  70  for a small distance, such that the baffle does not provide an integral expansion chamber for propellant gases. Rather, the baffles  22  only provide the gas check feature and do not provide a propellant gas expansion feature within the tubular bodies  70  of the baffles  22 . The gas check feature prevents propellant gases from passing around a bullet traveling through the suppressor  12 . The tubular body  70  is preferably imperforate, such that a sidewall  72 , an outer surface  74  and an inner surface  76  are continuous and without perforations or other openings through which propellant gases could flow. Both the outer surface  74  and the inner surface  76  of the sidewall  72  are substantially uniform except for an annular-shaped upset  78 . An end bevel  80  is provided on the rearward end of the cylindrical body  72  of the baffle  22  to aid in inserting the baffle  22  into the baffle tube  20 . It should be noted that the volume of the interior of the cylindrical body  72  is such that it does not provide for expansion of propellant gases, but merely passage of a bullet projectile there through, with the continuous inner surface  76  being nearly the same size as the outside diameter of a bullet projectile. 
       FIG. 11  is a longitudinal section view of the sound suppressor  12  as would be viewed if taken along section line  3 - 3  of  FIG. 1 , when used with an alternative baffle tube  88  instead of the baffle tube  20  and the baffles  22 . Similar to the baffle tube  20  of  FIGS. 3 and 5 , the alternative baffle tube  88  is imperforate, being continuous and not having any ports extending through a sidewall  94  of the baffle tube  88  to connect the interior of the baffle tube  88  to the expansion chamber  56 . The propellant gases only pass through flow ports  36  in the muzzle cap  16 , and not through any portion of the sidewall  94  of the baffle tube  88 . The longitudinal axis  58  extends centrally through the suppressor  12 , co-axial with the exterior tube  14 , the muzzle cap  16 , the end cap  18 , and is coaxial with the baffle tube  88 . The baffles  22  of  FIG. 3  are not used with the alternative baffle tube  88 , but instead the interior bore  96  of the baffle tube  88  is sized to both freely pass a bullet passing through the suppressor  12  and provide a gas check feature in which propellant gases are prevented from flowing past a bullet passing through the suppressor  12 , such that most of the propellant gases are forced to pass through the vent ports  36  and into the expansion chamber  56 . 
       FIG. 12  is a longitudinal section view of the alternative baffle tube  88  of the sound suppressor  12  of  FIG. 11 . The baffle tube  88  has a rearward end defined by a first end  90  and a forward end defined by a second end  92 . Preferably the first end  90  and the second end  92  are of uniform shape, not having threads nor peripheries with reductions in diameter. The baffle tube  88  has a tubular body with a sidewall  94  which is imperforate, that is, the sidewall  94  is continuous since it is without perforations or other openings through which propellant gases could flow and without upsets. The baffle tube  88  has the interior bore  96 . 
     The present invention provides advantages of a firearm suppressor having a single expansion chamber which is annular-shaped and runs the full length of the firearm suppressor. Fluid communication between the central bore of the suppressor and the expansion chamber occurs only at the rearward end of the suppressor, adjacent to the firearm muzzle to which the suppressor is mounted. A plurality of baffles each provide gas brakes and do not have internal expansion chambers nor flow passages passing through sidewalls thereof and into an external expansion chamber. A plurality of pressure relief ports are provided by vent ports located in a circumferentially extending section in the end cap. A restricted central bore of the suppressor provides the gas check feature to prevent spent propellant gases from moving past a bullet passing through the suppressor, causing a majority portion of the propellant gases to pass through vent ports located by a firearm gun barrel muzzle and into the expansion chamber. 
     Although the preferred embodiment has been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.