Abstract:
A coupling system attaches a device such as a blank adaptor or a sound suppressor to the flash hider of a firearm. The device is slid over the flash hider until a set of flat surfaces on it are aligned with a set of holes in the device. Camming latches are held in the holes in the device. The collar carried by the device is then threadably advanced to a locking position with respect to the device where it presses the camming latches into secure engagement with the flat surfaces on the flash hider. Unthreading the collar to the unlocked position allows the camming latches to be moved radially when the device is to be removed or rotated. A spring lock prevents the collar from rotating during use, particularly during firing of the firearm but may be released to rotate the collar between locked and unlocked positions.

Description:
PRIORITY CLAIM 
     The priority benefit of U.S. provisional patent application 61/375,620, filed Aug. 20, 2011, is claimed. This patent application is related to U.S. provisional patent application Ser. No. 61/375,339 and Ser. No. 61/375,570, both also filed Aug. 20, 2010. Applications 61/375,620, 61/375,339 and 61/375,570 are all incorporated herein in their entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Blank adapters and sound suppressors are examples of devices that are sometimes attached to the muzzle of a military style firearm. The muzzle typically includes a flash hider threaded to the end of the barrel and these devices are fitted to the flash hider. 
     Blank adaptors are used in training to allow the firearm to fire “blank”, as opposed to “live”, rounds of ammunition. If the combustion gases from the firing of a blank are allowed to escape from the unrestricted muzzle of a gun, there is insufficient back pressure to chamber the next round. A blank adaptor restricts the exit of the muzzle so that there is sufficient back pressure for chambering that next round. 
     A sound suppressor may also be fitted to the end of a gun to absorb the sound and minimize the flash of the fired round so as to reduce the likelihood that the marksman&#39;s position will be detected. 
     SUMMARY OF THE INVENTION 
     The present invention is a coupler system for attaching devices such as blank adaptors and sound suppressors to the flash hider of a firearm. Blank adaptors and sound suppressors will be referred to herein simply as “attachable devices”, or simply “devices” for convenience. Prior art devices may be modified for use in the present coupler system. Other than that modification, the balance of a prior art attachable device is in all other respects unchanged; that is, if the prior art device is a blank adaptor, those of its features that cause it to operate as a blank adaptor remain unchanged. Those features that connect it to a firearm on the other hand will be modified in accordance with the present invention to interface with the balance of the present coupler system. Similarly in the case of a sound suppressor, those portions of the suppressor that function to suppress sound remain unchanged but those features that are intended to attach it to a firearm are modified in accordance with the present invention. 
     The present coupler system includes an attachable device, a collar, plural camming latches, a spring lock, and a stop ring to secure the collar to a device, all of which comprise the present coupler system. The attachable device may be a blank adaptor or sound suppressor or the like. 
     The locking collar surrounds the proximal end of the attachable device. The collar is threaded on the inside, and the attachable device, threaded on the outside to enable the collar to advance toward or retreat from the distal end of the attachable device depending on whether the collar is rotated clockwise or counter-clockwise, respectively. The attachable device has cutouts formed through its peripheral wall at its proximal end. These cutouts are dimensioned to receive the camming latches, and to enable them to engage the flash hider inside the collar and thereby help to hold the attachable device to the flash hider. As the collar advances, its interior surface cams the camming latches, held against axial movement by the cutouts, against the exterior of the flash hider, thus locking the device to the flash hider. The spring lock prevents the collar from backing itself out of that locked position, and the stop ring limits proximal travel of the collar when the collar is moved out of the locked position. 
     An important feature of the present invention is the use of plural camming latches to lock the attachable device to the flash hider. This arrangement provides a secure way to lock the attachable device to the flash hider with a gas tight seal, but it also allows the attachable device to be attached in different rotational orientations. The significance of this feature is especially important when the attachable device is a sound suppressor. Each rotational orientation of a suppressor on a flash hider will have a slightly different effect on the trajectory of rounds fired by that firearm. One of those orientations will have the least effect, one that is ideally or potentially an effect small enough to make re-zeroing the firearm with the suppressor unnecessary. Once that position is known, the device can be attached in the same rotational orientation each time and the marksman will know that the firearm will perform in a manner similar to the way it does without the device. 
     Other features and their advantages will be apparent to those skilled in firearm attachments from a careful reading of the Detailed Description of Preferred Embodiments, accompanied by the following drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the figures, 
         FIG. 1  is an exploded view of a coupler system for attaching a sound suppressor to a flash hider of a firearm, according to an embodiment of the present invention; 
         FIG. 2  is an exploded view of a coupler system for attaching a blank adaptor to the flash hider of a firearm, according to an embodiment of the present invention; 
         FIG. 3  is a cross-sectional side view of a coupler system in the unlocked position, according to an embodiment of the present invention; 
         FIG. 4  is a cross-sectional side view of the coupler system of  FIG. 3  shown in the locked position, according to an embodiment of the present invention; 
         FIG. 5  is a cross-sectional view taken along lines  5 - 5  of  FIG. 3 ; 
         FIG. 6  is a cross-sectional view taken along lines  6 - 6  of  FIG. 4 ; 
         FIG. 7  is a cross-sectional view taken taken along lines  5 - 5  of  FIG. 3  showing the operation of spring lock in enabling rotation of the attachable device; 
         FIG. 8  is an exploded perspective view of an alternative embodiment of the present coupler system having a different spring lock; 
         FIG. 9  is an exploded perspective view of yet another alternative embodiment of the present invention having a different spring lock and spherical camming latches; 
         FIG. 10  is a side cross-sectional view of a coupler system shown in the locked position, according to the embodiment of  FIG. 9 ; 
         FIG. 11  is a side cross-sectional view of a coupler system shown in the unlocked position, according to the embodiment of  FIG. 9 ; and 
         FIG. 12  is a cross-sectional view of the coupler system showing the spring lock taken along lines  12 - 12  of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention is a coupling system for attaching an attachable device such as a sound suppressor or blank adaptor to the flash hider of a firearm. The device and the flash hider are part of the present invention. However, the flash hider and device may be prior art sound suppressors and blank adapters modified to accommodate the present coupling system while their functional aspects, namely, their respective structures for suppressing sound and enabling a firearm to fire blank ammunition in the same manner as live ammunition, are otherwise the same as before. 
       FIGS. 1-7  illustrate a first embodiment of the present coupler system;  FIG. 8  illustrates the present coupler system with an alternative spring lock;  FIGS. 9-12  illustrate an alternative embodiment of the present coupler system having another alternative spring lock. 
     Referring now to  FIGS. 1 and 2 , there are shown two exploded perspective views of the present coupler system, generally indicated by reference number  20 . In  FIG. 1 , coupler system  20  includes an attachable device  22  that is a sound suppressor. In  FIG. 2 , coupler system  20  includes attachable device  22  that is a blank adaptor. In both  FIGS. 1 and 2 , the proximal end of attachable device  22  is modified in the same way, namely, a gear surface  24  is formed at its most proximal end (proximal determined from the point of view of the one firing the firearm) followed by a annular region  26  with cutouts  28  formed there through. Annular region  26  is in turn followed in the distal direction by a threaded region  30  with threads  32 . Blank adaptor also has a stem  34  and the suppressor has a shoulder  36  both of which are distal to threads  32  and used to index the coupler. The balance of the suppressor ( FIG. 1 ) and the blank adaptor ( FIG. 2 ) have such internal features as suppressors and adaptors normally have; only the proximal ends are modified as just described. 
     Coupler system  20  is made to be used with a firearm with a barrel on which is fastened a flash hider such as flash hider  40  in  FIGS. 1 and 2 , which may also be a prior art flash hider modified for use with coupler system  20 . In the embodiment shown, flash hider  40  is made or modified to have flat surfaces  42  or other latch-engaging surface configuration. 
     U.S. provisional patent application Ser. No. 61/375,339 and Ser. No. 61/375,570, both filed Aug. 20, 2010 are related applications for examples of attachable devices  22  and a flash hider  40  and are incorporated in their entirety by reference. 
     Coupler system  20  includes a collar  50 , a stop ring  52 , a spring lock  54  with springs  56  and  58  and camming latches  60 . Camming latches  60  have a bottom surface that may conform to the latch-engaging portion of flash hider  40 . If that portion is flat; the bottom side of camming latches  60  is flat as shown; if it is curved; the bottom side of camming latches is curved with the same radius of curvature. Spring lock  54  pivots about a pivot pin  62  which is inserted into a hole  64  through collar  50  and through a hole  66  through spring lock  54  to enable spring lock  54  to pivot freely against the urging of springs  56 ,  58 . Camming latches  60  fit into cutouts  28  in annular region  26  of attachable device  20  where they can engage flat surfaces  42  of flash hider  40 . There they are held against axial movement but are able to move radially. Finally, stop ring  52  is a spring lock that snaps into an annular groove  70  on flash hider and there acts as a stop to prevent removal of collar  50  in the proximal direction when unlocking collar  50 . 
     Referring now to  FIGS. 3 and 4 , there are shown cross-sectional views of coupler system  20  in the unlocked and locked positions, respectively. Attachable device  22  in these figures is blank adapter but may be a different type of attachable device  22 . In  FIG. 3 , collar  50  is shown moved in the proximal direction where its rearward motion is stopped by stop ring  52 . In this position, flash hider  40  may be withdrawn from device  20  or attachable device  22  may be rotated about its axis. When flash hider  40  is withdrawn, a distal wall  86  on its interior surface that marks the distal boundary of flat surface  42 , and which wall  86  is inclined, will cam against the corresponding angled distal wall  74  of camming latch  60  thereby urging camming latch  60  to move radially outward against collar  50 . Because collar  50  is in the unlocked, proximal position, there is sufficient space between it and camming latch  60  for camming latch  60  to move radially outward by enough distance to allow flash hider  40  to clear camming latch  60  from below. However, when collar  50  is in the locked position ( FIG. 4 ), radial movement of camming latch  60  is prevented by the engagement of collar  50  against the upper surface  80  of camming latch  60 . Collar  50  has an interior surface  78  formed to engage upper surface  80  of camming latch  60  and apply pressure to it when the lower surface  82  of camming latch  60  is already pressing against hider  40  and the forward surface  86  of camming latch  60  is engaging the side surface  90  of flash hider  40 . Having no other direction left to which it can move when collar  50  is in the locked position, camming latch  60  thus prevents proximal movement of flash hider  40 . 
     Flash hider  40  has an annular stepped-down portion, or, more precisely, ramped-down portion  104 , as it is angled at less than 90° with respect to the long dimension of flash hider  40  where the diameter of flash hider  40  narrows slightly. Device  22  has a corresponding rampeddown portion  106  where its wall thickness gradually increases. Ramped-down portions  104  and  106  are located so that they seal against each other when device  22  is mounted to flash hider  40  and threaded thereto by rotating collar  50 . As spherical camming latches  60  enter cutouts  28 , they exert pressure on the seal between ramped-down portions  104 ,  106 , making them gas tight while, at the same time, preventing collar  50  from backing off device  22 . 
       FIGS. 5 ,  6 , and  7  illustrate the operation of spring lock  54 . Spring lock  54  prevents rotation of collar  50 , either when in the unlocked position ( FIG. 3 ) or in the locked position ( FIG. 4 ). Spring lock  54  operates like a pawl on gear surface  24 , pivoting about its pivot pin  62 . When its first end  96  is pressed against the urging of compression springs  56 ,  58  to pivot its opposing second end  98  out of engagement between the teeth  100  of gear surface  24  (as best seen in  FIG. 7 ), collar  50  is freed and can be rotated between its locked and unlocked positions with respect to attachable device  22 . Releasing first end  96  of spring lock  54  causes second end  98  of spring lock  54  to again engage teeth  100  of gear surface  24 . 
     Referring now to  FIG. 8 , there is illustrated an exploded view of a coupler system  20 ′ that is in almost every respect the same as that illustrated in  FIGS. 1 and 2 , save for the spring lock  54 ′. Spring lock  54 ′ pivots about a pivot pin  62 ′ that is oriented 90 degrees from that of pivot pin  62 . Accordingly the orientation of spring lock  54 ′ is rotated 90 degrees from that of spring lock  54 . However, its operation is essentially the same: by pressing on a first end  96 ′ against the urging of spring  56 ′, the opposing second end  98 ′ of spring lock  54 ′ lifts free of gear surface  24  and allows collar  50  to be rotated and advanced or retreated with respect to attachable device  22 . 
     Referring now to  FIGS. 9-12 ,  FIG. 9  illustrates the components of the present coupler system, generally indicated by reference number  110 , in an exploded view. In this view, a flash hider  112  is shown with a proximal end  114  and opposing distal end  116 . Proximal end  114  is formed with interior threads in order to allow hider  112  to be threaded to the barrel of a firearm (not shown). Distal end  116  is also formed with three gaps  118  around its annular opening. Between proximal end  114  and distal end  116  is a region  120  with a hexagonal cross-section so as to permit a wrench to be used to fasten flash hider  112  to the barrel. 
     Proximate to region  120  are six partial, spherical cutouts  124  serving as the latch-engaging surface of this embodiment rather than the flat surfaces  42  described above. The purpose of these six partial, spherical cutouts  124  will be explained below. 
       FIG. 9  also shows an attachable device  130  having an opening  132  at a proximal end  134  and, at the opposing distal end  136 , a small opening  138  (see  FIGS. 10 and 11 ). Device  130  is similar to prior art blank adaptors and sound suppressors and its structure for performing in either of those capacities is conventional. However, device  130  is modified for the present coupler system  110 . 
     In particular, device  130  has an annular flange  140 , exterior threads  142  proximal to annular flange  140 , a series of six circular holes  144  formed in its peripheral surface proximal to exterior threads  142 , a band of scalloped recesses  146  near its proximal end  134 , and an annular spring groove  148  at its proximal end  134 . The function of these features will be explained below as well. 
     A set of six spherical camming latches or other number sufficient to adequately retain the device  130  are used to lock coupling system  110  in the following manner. These six spherical camming latches  150  are inserted in the six holes  144  formed about the surface of device  130 . A number of spherical camming latches other than six may be used if the number of holes  144  is correspondingly adjusted to be at least equal to the number of spherical camming latches  150 . Preferably, the total number of holes  144  and spherical camming latches  150  is greater than two, producing a self-centering effect. 
     System  110  includes a collar  156  having interior threads  158  that mate with exterior threads  142  of device  130 . Collar  156  also has a tapered annular groove  160  and a stepped portion  162  having a recess  164  with a hole  166  formed in collar  156  along with interior threads  158 . 
     Finally, system  110  also includes a wire spring  170  with a loop  172  at one end and a catch  174  at the other end. 
     Wire spring  170  is inserted into the interior of collar  156  against stepped portion  162  with catch  174  inserted in hole  166  of recess  164 . Loop  172  of wire spring  170  is inserted in the closest scalloped recess  164  on the surface of device  130  (see  FIG. 12 ) as collar  156  is slid over proximal end  134  of device  130 , thereby mating interior threads  158  of collar  156  with exterior threads  142  of device  130 . Stop ring  176  is fitted to annular groove  148  after collar  156  is in place to secure collar  156  to device  130 . See  FIGS. 10 and 11 . Holes  144  of device  130  are alignable with partial, spherical cutouts  124  on flash hider  112  by rotating device  130  with respect to flash hider  112 . Spherical camming latches  150  are held in tapered annular groove  160  and holes  144  as collar  156  is rotated. Once spherical camming latches  150  are seated in partial spherical cutouts  124 , collar  156  can not be advanced and wire spring  170  holds collar  156  in place with respect to device  130 . 
     Flash hider  112  has an annular stepped down portion, or, more precisely, ramped-down portion  180  as it is angled at less than 90° with respect to the long dimension of flash hider  112  where the diameter of flash hider  112  narrows slightly. Device  130  has a corresponding ramped-down portion  182  where its wall thickness increases. Ramped-down portions  180  and  182  are located so that they seal against each other when device  130  is mounted to flash hider  112  and threaded thereto by rotating collar  156 . As spherical camming latches  160  enter spherical cutouts  124 , they exert pressure on the seal between ramped-down portions  180 ,  182 , making them gas tight while, at the same time, preventing collar  156  from backing off device  130 . 
     As collar  156  is threaded to device  130 , tapered annular groove  160  cams spherical camming latches  150  radially inward, into partial, spherical cutouts  124  where they lock device  130  to flash hider  112 . Also, as collar  156  is rotated, looped end  172  of wire spring  170  is urged from one scalloped cutout  146  to the next in the band of scalloped cutouts  146  (see  FIGS. 9 and 12 ) by the force applied by the user in rotating collar  156  clockwise. That force also works to prevent collar  156  from inadvertently backing off device  130 , even when the firearm is in use. 
     Coupling system  110  operates to securely lock device  130  to flash hider  112  and to keep it locked during use. In addition to this primary function, it will be noted that the holes  144  of device  130  may be positioned in one of six possible ways (given the presently illustrated embodiment of six holes  144  and six spherical camming latches  150 ) with respect to the partial spherical cutouts  124 . If the firearm has been properly zeroed, that is, its sights have been adjusted for the particular marksman and for the ammunition being used, but without device  130  mounted to the barrel of the firearm (and if device  130  is a sound suppressor rather than a blank adaptor), then the addition of device  130  will inevitably have an effect on the marksman&#39;s accuracy however small that effect may be. That effect will vary very slightly from one to another among these six positions. One of them, however, will affect the marksman&#39;s accuracy less than the others. The marksman can mark the hole  144  in device  130  corresponding to the position having the least effect on accuracy so that he or she can align device  130  and flash hider  112  the same way each time device  130  is threaded to hider  112 . 
     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.