Patent application title: Mounting system for muzzle devices and firearms
James Kenneth Dickerson (Brunswick, GA, US)
Clyde Augustus Wilson Jr., Iii (Woodbine, GA, US)
IPC8 Class: AF41C2700FI
Class name: Firearms muzzle making, attaching or repair
Publication date: 2011-06-30
Patent application number: 20110154711
A system for connecting an accessory to a firearm having a muzzle device
has a plurality of swinging arms pivotally connected to a body. The
swinging arms releasably engage a portion of the muzzle device. The
swinging arms are operable for movement between a closed position and
open position. The swinging arms have a retention feature sized to
receive a rear portion of the muzzle device when the swinging arms are in
the closed position. The swinging arms have a locking mechanism that
releasably secures them together to prevent movement of the swinging arms
to the open position, so that the accessory may be removed or installed
when in the open position, and secured when in the closed position. A
bore of the body may closely receive at least a portion of the muzzle
1. A facility for connection to a firearm with a barrel extending to
define a forward direction, the barrel having a muzzle device, the
facility comprising: a body; a plurality of swinging arms pivotally
connected to the body; the swinging arms releasably engaging a portion of
the muzzle device; the swinging arms being operable for movement between
a closed position and an open position; the swinging arms each having
opposing internal surfaces; the internal surfaces each defining a
retention feature sized to engage the muzzle device when the swinging
arms are in the closed position; and the swinging arms having a locking
mechanism that releasably secures the swinging arms together to prevent
movement of the swinging arms to the open position.
2. The facility of claim 1 wherein the retention feature includes a flattened portion that engages a wrenchable flat on the rear portion of the muzzle device.
3. The facility of claim 1 wherein the retention feature includes a circumferential ridge that engages a groove on the rear portion of the muzzle device.
4. The facility of claim 1 wherein the body defines a bore.
5. The facility of claim 4 wherein the bore of the body closely receives at least a portion of the muzzle device.
6. The facility of claim 4 wherein the body includes a functional device having a bullet passage, the functional device selected from the group of devices including sound suppressors, muzzle brakes, adapters, and launching apparatus.
7. The facility of claim 1 wherein the locking mechanism comprises: a screw having a secured end and a free end with the secured end pivotally attached to one of the swinging arms; a nut threadedly attached to the free end of the screw the swinging arms each defining a slot in one end; one of the slots receiving the secured end of the screw; one of the slots receiving the free end of the screw when the swinging arms are in the closed position; and the nut being secured within the slot receiving the free end of the screw when the swinging arms are in the closed position.
8. The facility of claim 1 wherein the muzzle device has a flat surface, and at least one of the arms has an engagement surface operable to contact the flat surface when the arm is in the closed position, such that the facility is prevented from rotating with respect to the muzzle device.
9. The facility of claim 1 wherein the body includes a tube extending forward of the facility.
10. The facility of claim 1 wherein the arms are generally semi-cylindrical bodies.
11. A method of removably securing a device to a firearm barrel having a muzzle device with a free end extending in a forward direction, comprising the steps: providing a body having a bore sized to closely receive the muzzle device; providing a plurality of swinging arms attached to the body, the swinging arms being operable for movement between a closed position and an open position; providing a locking mechanism that releasably secures the swinging arms together to prevent movement of the swinging arms to the open position; unlocking the locking mechanism; moving the swinging arms to the open position; inserting the free end of the muzzle device into the bore; moving the body in a rearward direction until a rear portion of the muzzle device is aligned with a retention feature defined by an internal surface on each of the swinging arms; moving the swinging arms to the closed position, thereby engaging the retention features with the rear portion of the muzzle device; and locking the locking mechanism, such that the swinging arms are secured in the closed position.
12. The method of claim 11 wherein the locking mechanism includes a screw having a secured end and a free end with the secured end pivotally attached to one of the swinging arms and a nut threadedly attached to the free end of the screw, wherein one of the swinging arms defines a slot, and wherein the step of unlocking the locking mechanism includes rotating the nut counterclockwise to disengage the nut from the slot to permit movement of the swinging arms to the open position.
13. The method of claim 11 wherein the locking mechanism includes a screw having a secured end and a free end with the secured end pivotally attached to one of the swinging arms and a nut threadedly attached to the free end of the screw, wherein one of the swinging arms defines a slot, and wherein the step of locking the locking mechanism includes rotating the nut clockwise to secure the nut within the slot to prevent movement of the swinging arms to the open position.
FIELD OF THE INVENTION
 The present invention relates to firearms, and more particularly to facilities for mounting on the muzzle a device, such as a sound suppressor, muzzle brake, recoil compensator, or blank firing adapter.
BACKGROUND OF THE INVENTION
 It is often desirable to mount removable devices at the muzzle of a firearm. A sound suppressor or silencer reduces the sound of the discharge of a firearm; a muzzle brake or compensator reduces recoil forces; a blank firing adapter is useful for training and for launching of grenades and rescue devices.
 A conventional muzzle mounted accessory may be internally threaded to engage a threaded end of a firearm barrel. This has the disadvantage of being slow to mount and dismount, which is a serious concern in military and law enforcement contexts. Other prior art mounts provide quicker disconnection, but suffer other disadvantages such as inadequate repeatable precision of alignment (which generates shooting inaccuracy), complexity and cost of manufacture, and durability. Other prior art systems require modification of the firearm, and proprietary adapter components. Because military regulations prohibit personnel from modifying their weapons, prior art devices that require replacement of muzzle-mounted components with proprietary adapters are considered unsuitable for many military applications.
 A number of patents have been granted for mounting muzzle devices, such as sound suppressors, to firearms. Various approaches also exist in the practiced prior art. However, there are a number of problems with prior art patents and existing practiced prior art. These problems include unwanted modifications to the barrel, the undesirable requirement of a proprietary flash hider, and the associated costs and time due to the installation of a proprietary flash hider. One of the major problems is that existing systems require modifications to the host firearm. These modifications either mean the machining of the existing barrel to accommodate the mounting system, or the installation of proprietary flash hiders that allow for the attachment of muzzle devices such as sound suppressors.
 To minimize these problems, there have been a number of different approaches that have been used in past years. One approach has been to specially design the host firearm to allow for attachment of a sound suppressor. This adds an unwanted burden at the stage of designing the firearm, and requires that the firearm manufacturer be cognizant of a possible requirement to attach a sound suppressor to the firearm as part of the design criteria.
 Another approach has been to design the mounting system to allow mounting to the existing flash hider on the standard rifle, and U.S. Pat. No. 5,773,746 (Vaden) is an example of this approach. This patent discloses a mounting system that allows for the quick attachment and detachment of a sound suppressor to the M4/M16A2 series of rifles that are equipped with a standard flash hider or compensator. The Vaden patent features the use of 3 pivoting fingers that are moved into position and locked onto the rear of the flash hider via the use of a rotating collar. A combination of left and right hand threads in the rotating collar and body of the mount meant that the collar was simply and quickly rotated one way to lock and the other way to unlock the sound suppressor from the flash hider.
 Another example of a mounting system utilizing an existing flash hider on a standard rifle is U.S. Patent Application 2007/0095198 A1 (Dater et al.). This patent application discloses a body with a bore sized to closely receive an enlarged muzzle portion of a firearm. The body has a stop to limit the insertion depth of the muzzle. The Dater patent features a gate that is received by the body for movement along the path perpendicular to the bore axis. The gate has a recessed area sized to receive the enlarged muzzle portion. A spring generates axial force to retain the muzzle portion within the recessed area. Compression of the spring enables movement of the gate to shift between an open and closed position, so that the accessory may be removed or installed when in the open position, and secured when in the closed position.
 G.B. Patent 2,242,476 (Felton) discloses a mounting system that allows a sound suppressor or muzzle device to be fitted to a wider variety of military rifles, which may be fitted with different length flash hiders that are conventionally threaded for attachment to a threaded muzzle. However, the design utilized a U-shaped cutout in a locking collar to accommodate the various flash hiders, and this collar was then secured to the rear of the flash hider by tightening up the suppressor (and subsequently the collar to the sound suppressor) against the front end of the flash hider. Screwing down the suppressor generates compression of the flash hider.
 Another approach used by Knight Armament Company and Brugger & Thonet, AG, is the use of a U-shaped locking gate that fits onto a proprietary flash hider and which is held under spring tension to the flash hider via an enlarged BFA (Blank Firing Adapter) groove that is machined into the exterior of the flash hider near the rear end of the flash hider. To ensure that the suppressor did not detach due to spring failure, a secondary retention system was added to the mount to ensure that the suppressor stayed attached to the host rifle if spring failure occurred.
 The approach of installing a proprietary attachment is also typified by U.S. Pat. No. 6,948,415 (Matthews et al) where the sound suppressor is attached and secured to a one-piece adapter and compensator that extended back over the barrel. The suppressor attached to an annular ridge on the adapter through the use of a rotating ring having an opening that is concentric when open and eccentric when closed, thus locking the sound suppressor to the adapter and compensator. This method of attachment is also in the existing practiced prior art as used by Brugger & Thomet (B&T) of Switzerland with the mounting system used with the Rotex-II 5.56 mm sound suppressor. Rather than being attached to an annular ridge on an adapter and compensator as per the Matthews patent, the mounting system of the Rotex-II was secured to a standard M4/M16A2 compensator and secured the sound suppressor against the rear of the standard M4/M16A2 compensator.
 All of the above systems have significant disadvantages in terms of cost, reliability, durability, accuracy, and/or combinations of these, at least for certain applications and needs. None of them attach directly to a standard M4/M16A2 compensator without any modification to the host weapon. All of the abovementioned mounting systems either require a separate compensator or the removal of the standard crush washer for attachment.
 It is therefore an object of this invention to provide a mounting system that provides a quick, secure and mechanically strong mounting system for muzzle devices such as sound suppressors, muzzle brakes, recoil compensators and BFAs (Blank Firing Adapters) to a firearm, that secures the muzzle device to the firearm regardless of vibrations from firing of the rifle, and allows for the quick and easy removal of the muzzle device from the firearm.
SUMMARY OF THE INVENTION
 The present invention provides an improved mounting system, and overcomes the above-mentioned disadvantages and drawbacks of the prior art. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide an improved mounting system that has all the advantages of the prior art mentioned above.
 To attain this, the preferred embodiment of the present invention essentially comprises a system for connecting an accessory to a firearm having a muzzle device has a plurality of swinging arms pivotally connected to a body. The swinging arms releasably engage a portion of the muzzle device. The swinging arms are operable for movement between a closed position and open position. The swinging arms have a retention feature sized to receive a rear portion of the muzzle device when the swinging arms are in the closed position. The swinging arms have a locking mechanism that releasably secures them together to prevent movement of the swinging arms to the open position, so that the accessory may be removed or installed when in the open position, and secured when in the closed position. A bore of the body may closely receive at least a portion of the muzzle device. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached.
 There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a front perspective view of the current embodiment of the mounting system constructed in accordance with the principles of the present invention installed on the gun barrel of a rifle.
 FIG. 2 is a rear exploded perspective view of the current embodiment of the mounting system of the present invention.
 FIG. 3 is a front exploded perspective view of the current embodiment of the mounting system of the present invention.
 FIG. 4 is a rear perspective view of the current embodiment of the mounting system of the present invention in a first stage of installation.
 FIG. 5 is a rear perspective view of the current embodiment of the mounting system of the present invention in an installed condition.
 FIG. 6 is a sectional side view of the current embodiment of the mounting system of the present invention in an installed condition.
 The same reference numerals refer to the same parts throughout the various figures.
DESCRIPTION OF THE CURRENT EMBODIMENT
 A preferred embodiment of the mounting system of the present invention is shown and generally designated by the reference numeral 10.
 FIG. 1 illustrates the improved mounting system 10 of the present invention installed on a rifle 12. More particularly, the rifle 12 has a barrel 14. The rifle has a rear end 20, and the barrel has a forward muzzle end 22. At the muzzle end is a permanently or temporarily mounted standard A2 compensator 34 (shown in FIGS. 2 and 3).
 In the application illustrated in the current embodiment, a sound suppressor 32 is prepared for installation at the muzzle. The sound suppressor 32 includes a tubular body 130 and the mounting system 10. The body 130 has an elongated forward portion 30 having an expansion chamber and including baffles and other functional elements. The front end 26 of the mounting system is removably attached to the rear portion 28 of the body to form the sound suppressor. The rear end 24 of the mounting system is removably connected to the A2 compensator and serves as a connection facility to provide a secure, reliable, repeatable, and rigid connection between the sound suppressor and the rifle. The mounting system attaches directly to the A2 compensator without requiring any modification of the host weapon.
 FIGS. 2 and 3 show the A2 compensator 34 and the components of the mounting system 10. The A2 compensator is a generally hollow cylindrical form defining a standard 1/2 inch×28 threads per inch threaded bore 104 at its rear 46 and a ring-shaped opening 58 at its front 48. The top 110 of the sidewall 52 of the A2 compensator is solid, while the bottom 112 of the sidewall has a plurality of vents 60 divided by prongs 56. Two circumferential grooves 54 are present towards the rear of the sidewall immediately behind the top solid portion. The sides of the rear of the sidewall immediately behind the grooves define two wrenchable flats 46.
 The A2 compensator is a standard recoil compensator designed to reduce muzzle rise during firing. However, the concepts of the preferred embodiment may be applied for attachment to any of a wide range of suppressor types having certain characteristics, as will be discussed below. The A2 compensator reduces the visible signature of the burning gases that exit the rifle's muzzle when it is fired by directing the gases through the top vents machined into the A2 compensator. This is useful from a tactical standpoint because it prevents the muzzle from rising upwards and reduces muzzle flash generated by the burning powder.
 The main portion of the mounting system is an entry cap 44 that is a generally hollow cylindrical form defining a central bore 108. The entry cap has a rim 126 with a forward externally threaded portion 90 and a rear face 132. The threaded portion 90 engages the rear portion 28 of the sound suppressor body 130. The top 114 of the rim defines two shoulder bolt holes 92. The bore has smooth walls and is sized to closely receive the sidewall of the flash suppressor. A flange 96 protrudes from the rear face 132 of the entry cap, and a groove 128 is defined between the flange and the rear face of the rim. The top 114 of the front of the entry cap terminates in an arcuate protrusion 104. The arcuate protrusion is sized to fit closely over and align with the solid portion of the sidewall of the A2 compensator. The bottom 116 of the front of the entry cap terminates in an arcuate prong 106. The arcuate prong is sized to fit closely over and align with one of the prongs present on the bottom of the A2 compensator so as to avoid blocking any of the vents.
 A left locking arm 38 and a right locking arm 36 are generally semi-cylindrical bodies each having a shoulder bolt hole 42 at their tops 118 and 120. The locking arms operate to provide a secure and releasable connection between the suppressor and the rifle. The bottom 124 of the right locking arm defines a roll pin hole 84. The bottoms 122 and 124 of the left locking arm and right locking arm each define slots 76 and 78 (shown in FIG. 4). The front 26 of the tops 118 and 120 of the locking arms each define a relief cut 102. The relief cut 102 is sized to closely receive the entry cap's flange. The depth of the relief cuts defines how wide the locking arms are permitted to open. The interior surfaces 64 of the locking arms each define a groove 94 in their forward portion. The grooves 94 are sized to closely receive the entry cap's flange. The left locking arm and the right locking arm each define a ridge 70 and 72 that protrudes inwards. The ridges are sized to closely fit the rearmost groove 54 on the A2 compensator. The left locking arm 38 and the right locking arm 36 have a flattened portion of their interior surface at 66 and 68. The flattened portions are sized to engage the wrenchable flats on the A2 compensator.
 A 10-32 socket head cap screw 78 has external threads 100 that threadedly engage a threaded bore 98 in the bottom 88 of a knurl nut 80. The knurl nut 80 is a generally hollow cylindrical form with an open top 86 that communicates with the threaded bore. A 1/16 inch diameter×0.500 inches long roll pin 82 and two 0.187 inch×0.375 inch shoulder bolts 40 complete the mounting system 10.
 In the current embodiment the components of the mounting system are formed of steel or other hard and durable material that can provide repeated and close precision engagement with a steel muzzle element, such as the A2 compensator 34.
 FIG. 4 shows the current embodiment in a condition in which it is prepared for installation, in a rotated orientation to illustrate major features. The threaded bore 104 of the flash suppressor is screwed onto the muzzle portion of the gun barrel 14 using the wrenchable flats 50, and the rear portion 28 of the sound suppressor is screwed onto the threaded portion 90 of the entry cap. The knurl nut 80 has been unscrewed sufficiently to permit the socket head cap screw 78 to pivot within the slot 74 in the right locking arm about the roll pin 82 installed in the roll pin hole 84. In this condition, the knurl nut is not retained by the sides of the slot 76 in the left locking arm, thereby permitting the locking arms to separate from one another once the socket head cap screw has pivoted the knurl nut out of the way. The left locking arm 38 and the right locking arm 36 are depicted in their open position in which they have subsequently pivoted about the shoulder bolts 40 installed in their shoulder bolt holes 42 and the shoulder bolt holes 92 in the rim 126. The entry cap has been slid over the front 48 of the A2 compensator so that the arcuate protrusion 104 is aligned with the top solid portion of the A2 compensator and the arcuate prong 106 is aligned with one of the prongs on the bottom of the flash suppressor. The A2 compensator is positioned within the bore 108 of the entry cap so that the A2 compensator's rearmost groove is aligned with the ridges 70 and 72 on the interior surfaces of the locking arms.
 In FIGS. 5 and 6, the locking arms 38 and 36 have been closed so that their flattened portions 66 and 68 press against the flats 50 on the A2 compensator. The ridges 70 and 72 engage with the rearmost groove 54 on the A2 compensator. The flange 96 on the entry cap 44 engages with the grooves 94 in the locking arms. The socket head cap screw 78 has been pivoted about the roll pin 82 so that the knurl nut 80 is positioned above the slot 76 in the left locking arm. The knurl nut 80 has subsequently been screwed downward so that it is retained by the sides of the slot 76 in left locking arm, thereby creating a clamping action by the locking arms around the flange of the entry cap and the rear 46 of the A2 compensator.
 While the locking arms are locked closed by the knurl nut, the mounting system cannot slide axially because of the engagement of the locking arms' ridges with the flash suppressor's groove. The mounting system also cannot rotate because of the engagement of the locking arms' flattened portions with the A2 compensator's flats. The combined effects of the locking arms' ridges and flattened portions also ensure that the sound suppressor is positively axially registered with the gun barrel.
 Removal or =installation of the suppressor from the rifle muzzle follows the reverse process. The knurl nut must be unscrewed sufficiently to clear the sides of the slot 76 and left locking arm and pivoted out of the way so that the locking arms may be pivoted to their open position. Only then can the A2 compensator be withdrawn from the bore of the entry cap.
 By fixing the orientation of the sound suppressor with respect to the gun barrel using the mounting system, the accuracy of the rifle with the sound suppressor installed is assured despite multiple cycles of installation and removal of the sound suppressor. In order for the mounting system to be practical, a single sight-in session when the sound suppressor is installed on the rifle for the first time must be all that is required to ensure the rifle's accuracy.
 In the context of the specification, the terms "rear" and "rearward" and "front" and "forward" have the following definitions: "rear" or "rearward" means in the direction towards the muzzle of the firearm while "front" or "forward" means it is in the direction away from the muzzle of the firearm; "longitudinal" means in the direction of or in parallel with the longitudinal axis of the barrel while "transverse" means in a direction across the longitudinal direction.
 In use, a muzzle device such as an A2 compensator is attached to the barrel of a firearm. The A2 compensator has a cylindrical bore that aligns with the bore of the barrel of a firearm. A muzzle device, preferably a sound suppressor, is positioned over the A2 compensator in a concentric and axial alignment with the A2 compensator and the barrel of the firearm. The sound suppressor has a preferably round body with sound suppression structures that are well known in the art. At the front of the sound suppressor is a front end cap with an opening concentric to the bore of the firearm, while at the rear of the sound suppressor, a mounting system for attachment of the sound suppressor to the firearm is provided.
 The mounting system may be secured to the sound suppressor by well-known means such as threading, or may be permanently attached to the suppressor tube. While the embodiments described herein describe the use of threads for attachment to the sound suppressor, the use of threads is not exclusive and other methods of attachment such as welding or chemical adhesives may be used if so desired, or a combination of these methods may be used.
 When attaching the sound suppressor onto the flash suppressor and firearm barrel, the knurl nut is unscrewed and the locking arms are lifted in a vertical plane by rotating them about the shoulder bolts so the locking arms protrude as far as possible. This ensures that the entry cap can be placed on the A2 compensator and then moved rearwards without impediment from the locking arms.
 The entry cap is placed on the A2 compensator in a rearward movement by inserting the A2 compensator between the locking arms and into the entry cap. The A2 compensator is received by the bore of the entry cap. The rearward longitudinal movement continues until the rearmost groove of the A2 compensator is aligned with the ridges protruding inwards from the interior surfaces of the locking arms.
 At this stage, the locking arms are then fully pivoted until they are stopped by the contacting of their flattened portions with the A2 compensator's flats. The socket head cap screw is then pivoted on the roll pin to align the knurl nut with the slot in the left locking arm, and the knurl nut is then tightened down into the slot in the left locking arm. Once the attachment has been completed, the sound suppressor is secured to the A2 compensator in both longitudinal and rotational axes.
 To remove the suppressor from the A2 compensator, the knurl nut is first unscrewed to release it from the slot in the left locking arm. Once the socket head cap screw is pivoted to remove the knurl nut from the slot in the left locking arm, the locking arms are pivoted open until they can no longer be pivoted further. The entry cap is then removed from the A2 compensator in a forward longitudinal motion until it is removed completely from the A2 compensator.
 The mounting system thus described provides for a quick and easy, yet reliable and mechanically strong attachment system for muzzle devices, such as sound suppressors, to be attached to the barrel of a firearm that has an A2 compensator positioned on the forward portion of the firearm barrel.
 While a current embodiment of mounting system has been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. For example, while a sound suppressor is described as the preferred muzzle device that is attached to the mounting system disclosed herein, other muzzle devices such as muzzle brakes, recoil compensators and BFAs (Blank Firing Adapters) may also use the mounting system for attachment to an A2 compensator. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.