PRIORITY CLAIM 
     Priority is claimed to U.S. provisional patent application Ser. No. 61/375,530, filed Aug. 20, 2010; to U.S. non-provisional patent application Ser. No. 13/032,804 filed Feb. 23, 2011, which in turn claims priority to U.S. provisional patent application Ser. No. 61/309,047 filed Mar. 1, 2010; to U.S. provisional patent application Ser. No. 61/375,339, filed Aug. 20, 2010; and to U.S. provisional patent application 61/375,620, filed Aug. 20, 2010, all of which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     A military firearm may have a flash hider threaded to the end of its barrel. The flash hider is intended to reduce both the primary flash caused by the initial explosion of the powder charge when a round of ammunition is fired, and the secondary flash caused when the partially combusted gases and hot air from the barrel reignite following the shock of meeting the colder air surrounding the end of the barrel. The visible flash is an indication of the marksman&#39;s location. Hiding the flash makes it difficult to locate that marksman. 
     A sound suppressor reduces the sound of a firearm being fired for the same objective for which a flash hider reduces flash, namely, to make it more difficult to detect the location of the marksman. A sound suppressor is inherently a flash hider because it is typically a closed cylinder and thus prevents the flash from being seen while it performs its primary function of suppressing sound. 
     Both a flash hider and a sound suppressor are typically fitted to the threaded end of the barrel of a firearm. 
     SUMMARY OF THE INVENTION 
     The present invention is a combination of a flash hider, a sound suppressor and a coupler that holds the sound suppressor to a flash hider. The flash hider does not need to be removed to use the sound suppressor or replaced after the sound suppressor is removed. Furthermore, the coupler enables the suppressor to be attached to the flash hider rather than to the barrel proximate to the flash hider so that the flash hider forms a nozzle at the entrance to the sound suppressor and thereby facilitates the operation of the suppressor. The present coupler also enables the sound suppressor to be removed and installed quickly and securely. 
     A feature of the present flash hider is that it is characterized by three tines that are slightly tapered, that are long, and that contain stepped features on their sides that face the gaps between the tines. These stepped features expand the distance between the tines for hot gases traveling radially from the central bore of the flash hider and allow those gases to cool quickly. The steps also create turbulent mixing with the cooler air outside the flash hider to reduce the shock of the hot gases hiting the cooler air and to reduce the temperature differential between the two to avoid reignition and the attendant secondary flash. 
     A feature of the present sound suppressor is that its internal baffle structure moves a portion of the axial flow of high energy gases radially and into a path where those gases cross and re-cross the centerline of the suppressor to turbulently mix with the axial flow and more quickly give up heat to the baffles and to the suppressor housing itself for more effective sound suppression. 
     A feature of the coupler is that it can be quickly unlocked and rotated clockwise to secure a flash suppressor to a flash hider, or unlocked and rotated counter-clockwise to allow the suppressor to be removed. A spring lock automatically locks the coupler and is unlocked simply by pressing the spring lock handle. 
     These and other features and their advantages will be apparent to those of ordinary skill in the art from a careful reading the Detail Description of Embodiments accompanied by the following Drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the figures, 
         FIG. 1  is an exploded view of a coupler for attaching a sound suppressor to a flash hider of a firearm, according to an embodiment of the present invention; 
         FIG. 2  is a cross-sectional side view of a coupler shown locking a sound suppressor to a flash hider, according to an embodiment of the present invention; 
         FIG. 3  is a cross-sectional side view of the coupler of  FIG. 2  shown with the suppressor unlocked from the flash hider, according to an embodiment of the present invention; and 
         FIG. 4  is a cross sectional view taken along lines  4 - 4  of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present device is a quickly-disconnectable sound suppressor for a firearm. The device is also a quick-disconnect flash and sound suppressor for a firearm with a flash hider on the end of its barrel. Finally, the present device is a coupler for attaching a sound suppressor to a flash hider. 
     Referring now to  FIGS. 1-4 ,  FIG. 1  illustrates the components of the present flash and sound suppressor, generally indicated by reference number  10 , in an exploded view. In this view, a flash hider  12  and a sound suppressor  14  are coupled by a collar  16  using plural camming latches  18  and a spring lock  20 . 
     Flash hider  12  has a first or proximal end  30  and an opposing second or distal end  32 . Flash hider  12  is essentially a tube with a central bore  34  that defines a wall  36 . First end  30  has interior threads  38  that allow flash hider  12  to be threaded to the barrel of a firearm (not shown). Flash hider  12  has an exterior surface  40  that carries an annular recess  42  and, distal to recess  42 , several flat surfaces  44 . Toward its second end  32 , wall  36  of flash hider  12  has gaps  46  which define three tines  48 . 
     Tines  48  are long and tapered toward second end  32  and carry at least one step  50  on each side that faces gap  46 . A step  50  is a pair of angled changes in the surface of tines  48  that widen the distance from one tine  48  to the next as measured azimuthally, so that, when hot combustion gases from central bore  34  flow radially between tines  48  and through gaps  46 , they expand to cool. The side of a tine  48  is initially more or less radially directed. At a step  50 , that generally radial direction abruptly angles azimuthally away from the adjacent tine  48  and then returns abruptly to a generally radial direction much like a step in a stairway. 
     Suppressor  14  is a closed tube with a first or proximal end  60  and an opposing, second or distal end  62 . Suppressor  14  may be further defined by a first portion  64  and a second portion  66 . First portion is configured to receive flash hider  12  and to be coupled to flash hider  12  by collar  16 , as will be explained below. 
     First portion  64  has an opening  68  dimensioned to receive second end  32  of flash hider  12 . First portion  64  of flash hider  64  has an exterior surface  70  with a gear surface  72  at first end  60  followed by a series of annular holes  74  which are followed in turn by exterior threads  76 . These three features: gear surface  72 , holes  74  and exterior threads enable suppressor to be coupled to flash hider. 
     To couple, which means in this case to keep flash hider  12  and suppressor  14  locked together, the three camming latches  18  are first placed in annular holes  74  of suppressor. Then collar  16 , which has interior threads  90 , is slipped over first portion  64  of suppressor, as best seen in  FIGS. 2 and 3 . A spring ring  92  is then inserted in to annular recess  42  of flash hider  12  to limit movement of collar  16  in the proximal direction. Camming latches  18  are held by the interior surface  94  of collar  16  in place in holes  74  while holes  74  prevent their axial movement. When collar  16  is rotated clockwise, it advances distally toward sound suppressor  14 . As it advances, its interior surface  94  cams camming latches  18  against flat surfaces  44  on the exterior surface  40  of flash hider  12 . When collar  16  is rotated counter-clockwise, camming latches  18  are able to move radially outward while otherwise being retained within the space  96  between the interior surface  94  of collar  16  and flat surfaces  44  of flash hider  12  so flash hider  12  may be removed from coupler. 
     To prevent unintentional movement of collar  16 , spring lock  20  prevents its rotation. Spring lock  20 , as best seen in  FIG. 4 , has a pawl  100  with a first end  102  and an opposing second end  104  attached to collar  16  within a slot  106  by a pivot pin  108 . Two compression springs  110  and  112  urge first end  102  of pawl  100  to pivot away from collar  16  and a tooth  114  on second end  104  to pivot into engagement with gear surface  72  on first portion  64  of sound suppressor  14 . By pressing on first end  102  of pawl  100 , second end  104  is pivotally raised, and tooth  114  is lifted clear of gear surface  72 . Collar  16  is then free to be rotated clockwise or counter-clockwise to lock or unlock flash hider  12  from suppressor  14  or to simply rotate flash hider  12  with respect to suppressor  14 . 
     The attachment of a suppressor  14  to a firearm will inevitably affect the ballistic performance of the firearm. There are potentially six orientations of suppressor with respect to flash hider  12  if flat surfaces  44  are six in number such as would be the case if flash hider  12  had a hexagonal cross-section at the point between its first end  30  and its second end  32 . One of those six orientations will likely have the least impact on the ballistics and perhaps an impact that is so negligible that the firearm does not have to be re-zeroed. If so, that orientation can be marked by the user so that whenever the suppressor  14  is coupled to the flash hider  12  on the end of that particular firearm, the same rotational orientation of sound suppressor  14  can be obtained. 
     Inside second portion  66  of sound suppressor  14 , best seen in  FIG. 2 , tines  48  extend toward second end  62 , tapering and with gaps  46  allowing a portion of hot combustion gases to expand radially off center bore, thereby defining a nozzle. Distal to tines  48  is a blast baffle  120  with a front surface  122  that deflects radially flowing gases into a blind corner  124  between the housing  126  of suppressor  14  and blast baffle  120  while allowing other hot combustion gases to flow through a central hole  128  formed in blast baffle  120  for the bullet to pass through. 
     Blast baffle  120  has a rear surface  130  that acts as a second nozzle in directing a portion of those hot gases passing though central hole  128  radially while a remaining portion continues forward to a first disc baffle of plural disc baffles  132 . Each disc baffle  132  is a partial circular disc, with a central hole  134  and a radial opening  136  which may be formed simply by eliminating a section of what would otherwise be a perfectly circular shape. Housing  126  is formed with slots  138  along its length, as best seen in  FIG. 1 , which can receive disc baffles  132 . Disc baffles  132  can be secured in place by welding. Disc baffles  132  are arranged so that radial openings  136  are not aligned axially but are distributed in such a way as to define a path for hot gases to flow from flash hider  12  to second end  62  of suppressor  14  by crossing and recrossing the axis  140  of suppressor  14  until they exit through exit hole  142 . In crossing and recrossing axis  140 , turbulent mixing and disruption of the gases flowing through central holes  134  of disc baffles  132  by the radial gases accelerates the release of the kinetic energy of the gases to the disc baffles  132  and housing  126 . Baffles  132  and housing  136  act thus like a heat exchanger to absorb and radiate the heat from the hot gases passing though suppressor  14  to the surrounding air without flash and with greatly reduced sound. 
     Those familiar with firearms and their attachments will appreciate that many modifications and substitutions can be made to the foregoing preferred embodiments of the present invention without departing from the spirit and scope of the present invention, defined by the appended claim.
A flash hider, a sound suppressor and a quick-disconnect coupler that holds the sound suppressor to a flash hider is disclosed. The quick-disconnect coupler enables the suppressor to be attached to the flash hider so that the hider forms a nozzle at the entrance to the sound suppressor to facilitate the operation of the suppressor. The coupler includes a collar that threads to the first part of the suppressor over plural holes formed therein. Camming latches set in these holes are held firmly against flat surfaces on the exterior of the flash hider by the collar. A spring lock holds the collar against rotation until it is released.