Abstract:
The present folding stock adapter can be used with many types of military-type assault rifles that typically comprise a receiver extension, buffer and action spring. The present folding stock adapter can be used to add a folding capability to a standard stock allowing it to fold against a rifle&#39;s receiver when the weapon is not in use, thus reducing the overall length of the weapon. This reduction in length can facilitate its maneuverability, storage and transport in cramped quarters. The present device can also allow for the quick unfolding of the stock in order to allow the weapon to function and be fire normally.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of application Ser. No. 13/453,775, filed Apr. 23, 2012, which claims benefit to provisional application No. 61/600,686, filed Feb. 19, 2012, which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present device is an adapter comprising a hinge mechanism that can be used to add a folding capability to the stocks of many types of military-style assault rifles, including the well-known M-16 and AR-15. 
       BACKGROUND 
       [0003]    The utility of semi-automatic or automatic rifles can depend upon the physical size of the rifle, especially in military or law enforcement situations where space can be limited. For example, a longer rifle can be more unwieldy than a compact rifle within the cramped quarters of an armored vehicle, aircraft, or patrol car, making the transport, storage and maneuverability of the rifle cumbersome. Gunstocks often represent over one-third of the total length of any particular rifle, so the ability to fold the stock of a rifle against its remaining sections can significantly reduce the space required to store and maneuver the rifle. 
         [0004]    Many types of folding stocks currently exist for most military-style assault rifles. See U.S. Pat. No. 7,162,822 by Heayn et al. among many others. Additionally, various types of collapsible or telescoping stocks are also currently available. However, a collapsible stock apparatus does not fully solve the size problem because that type of stock slides along a rifle&#39;s receiver extension, which typically contains the buffer and action spring used to actuate such rifles. Therefore, these devices can only shorten the stock, by a length that does not include the receiver extension, which can often account for one-third or more of the total length of the stock. 
         [0005]    Alternatively, some folding stock adapters have been designed to allow fixed stocks the ability to fold. See U.S. Pat. No. 7,966,761 by Kuczynko et al. among many others. However, these existing folding stock adapters have been less than ideal; because certain parts of some military-style assault rifles, such as the action spring and bolt carrier, travel from the receiver of the firearm into the receiver extension, which is located within the stock of the rifle. Therefore, a folding stock adapter for such guns must be able to account for the weapon&#39;s bolt carrier, buffer and action spring when the weapon is either in a folded position or an unfolded position. The present workarounds for folding stock adapter have required reduced functionality in order to address this issue. 
         [0006]    What is needed is a folding stock adapter for use with military-style assault rifles which can accommodate the standard bolt carriers, buffers, receiver extensions and action springs comprising such weapons, which can also allow the stocks of such weapons to be folded over against the remaining parts of the rifle to substantially reduce its overall physical size, allowing easier transport, storage and maneuverability in space restrictive conditions, while allowing the rifle to be quickly unfolded to function and fire normally. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an aspect of the present device to provide a folding stock adapter, which can accommodate standard receiver extension, buffer, bolt carrier and action spring comprising many military-style assault rifles, that is capable of allowing a rifle&#39;s stock to fold securely against its receiver, thus reducing the length of the rifle by nearly the full length of the stock, but can also be quickly unfolded into a functional position and fired normally. The present folding stock adapter can be designed for use with any weapon that comprises a standard commercial or military-style receiver extension, buffer, bolt carrier and action spring. 
         [0008]    The above aspect can be obtained by a folding stock adapter comprising: a dead hinge section, configured to connect to a receiver; a live hinge section configured to connect to a stock; a hinged joint configured to connect the live hinge section to the dead hinge section allowing the live hinge section and dead hinge section to move between an open position and a closed position; a threaded flange configured to connect the dead hinge section to the receiver; and a bolt carrier extension. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Further features and advantages of the present device, as well as the structure and operation of various embodiments of the present device, will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
           [0010]      FIG. 1A  is an exploded rear, top and side perspective view drawing of a folding stock adapter and a receiver (prior art), such as those commonly comprising military-style assault rifles, according to an embodiment; 
           [0011]      FIG. 1B  is an exploded rear, top and side perspective view drawing of a bolt carrier assembly, including a bolt carrier extension, according to an embodiment; 
           [0012]      FIG. 1C  is a rear, top and side perspective view drawing of a bolt carrier assembly, including a bolt carrier extension, according to an embodiment; 
           [0013]      FIG. 2  is an exploded front, top and side perspective view drawing of a folding stock adapter and a receiver (prior art) such as those commonly comprising many military-style assault rifles, according to an embodiment; 
           [0014]      FIG. 3  is a rear, side, and bottom perspective view drawing of a folding stock adapter, in a closed position, connected to a receiver (prior art) such as those commonly comprising many military-style assault rifles, according to an embodiment; 
           [0015]      FIG. 4  is a rear, side, and top perspective view drawing of a folding stock adapter in a closed position, connected to a receiver (prior art) such as those commonly comprising many military-style assault rifles, according to an embodiment; 
           [0016]      FIG. 5  is a rear, side, and top perspective view drawing of a folding stock adapter in an open position, connected to a receiver (prior art) such as those commonly comprising many military-style assault rifles, according to an embodiment; 
           [0017]      FIG. 6A  is a side view drawing of a military-style assault rifle (prior art), comprising a folding stock adapter in a closed (fully functional) position, according to an embodiment; 
           [0018]      FIG. 6B  is a side view drawing of a military-style assault rifle (prior art), comprising a folding stock adapter in an open (folded) position, according to an embodiment; 
           [0019]      FIG. 7A  is a side, bottom and rear perspective view drawing of a folding stock adapter in a closed position, according to an embodiment; 
           [0020]      FIG. 7B  is a side, top and rear perspective view drawing of a folding stock adapter in an open position, according to an embodiment; and 
           [0021]      FIG. 8  is an exploded side and rear perspective view drawing of a standard rifle stock (prior art), receiver extension (prior art), action spring (prior art), buffer (prior art), bolt carrier extension, and live hinge section, according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    This description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. 
         [0023]    Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
         [0024]    The present folding stock adapter can be used to modify a military-style assault rifle using only the folding stock adapter, along with the rifle&#39;s standard stock, receiver, buffer, bolt carrier and action spring so that its stock can be configured to fold against the rifle&#39;s receiver, reducing the length of the weapon by nearly the full length of the stock. In an embodiment, the folding stock adapter can comprise a non-moving (in relation to the receiver) section, (referred to hereinafter as the “dead hinge section”) connected by a hinged joint to a moving section (in relation to the receiver), (referred to hereinafter as the “live hinge section”). The dead hinge section can be connected to the receiver of a typical military-style assault rifle by placing a threaded flange through the dead hinge section and screwing the threaded flange into a rear threaded section comprising many receivers. Similarly, the live hinge section can be connected to the stock of the assault rifle by screwing a receiver extension, such as those that typically comprise the stocks of most military-style assault weapons, into a threaded opening comprising the live hinge section. When the dead hinge section comprising the present folding stock adapter is connected to the receiver and the live hinge section is connected to the rifle&#39;s stock, the stock can be folded flat against the receiver when the folding stock adapter is in an open position. In an embodiment, the folding stock adapter can comprise a button or latch, which can be pressed in order to release the dead hinge section from the live hinge section, allowing the folding stock adapter to be moved from a closed position to an open position in order to fold the stock. 
         [0025]    Additionally, the present folding stock adapter also comprises a bolt carrier extension, which can compensate for the additional length added by the live hinge section and the dead hinge section buffer and bolt carrier can maintain proper contact and communication between them. 
         [0026]    The present folding stock adapter can be configured for use with multiple types of military-style assault rifles, including, but not limited to the M-16, M-4, AR-15, SR-25, M-110, AR-10 and HK-416, among others. The present folding stock adapter can be composed in full or in part of various metals, including, but not limited to, aluminum, steel, or any other alloys, plastics, carbon fiber, composites, or any other suitable materials known to those of ordinary skill in the art of firearm manufacturing. 
         [0027]      FIG. 1A  is an exploded rear, top and side perspective view drawing of a folding stock adapter  100  and a receiver  101 , such as those commonly comprising many military-style assault rifles, according to an embodiment. (The receiver  101  shown in  FIGS. 1A, 2, 3, 4, and 5  represents prior art, which is not part of the present folding stock adapter, but is shown only to provide a familiar point of reference.) 
         [0028]    In an embodiment, the folding stock adapter  100 , as depicted in  FIG. 1A , can be comprised of a dead hinge section  102  and a live hinge section  112 , wherein the dead hinge section  102  can be connected to the receiver  101  and the live hinge section  112  can be connected to a receiver extension (not shown in  FIG. 1A ) comprising the stock of the rifle. (Neither the receiver extension nor the stock comprise any part of the present folding stock adapter, but are standard parts comprising many military-style assault rifles.) 
         [0029]    In an embodiment, the dead hinge section tube  103  can comprise a first dead hinge section side  121 , a second dead hinge section side  122 , and a circular dead hinge section opening  123  within a dead hinge section tube  103 . The first dead hinge section side  121  can be configured to be secured to the rear threaded section  106  of the receiver  101 . The second dead hinge section side  122  can be configured to be connected to the live hinge section  112  and abut against the live hinge section  112  when the folding stock adapter  100  is in a closed configuration. In an embodiment, the second dead hinge section side  122  can comprise an indentation  127  configured to accept a connecting tab (not visible in  FIG. 1 ) comprising the live hinge section  112 , which can be used to secure the present folding stock adapter  100  in a closed position. 
         [0030]    In an embodiment, the dead hinge section  102  can comprise a circular dead hinge section opening  123  configured to allow a threaded flange  104  to pass mostly through the circular dead hinge section opening  123 . The threaded flange  104  can comprise a threaded body  145  which can be configured to be screwed into the rear threaded section  106  of the receiver  101 , where a receiver extension (not shown in  FIG. 1A ) would typically connect to the receiver  101 . The threaded flange  104  can also comprise a head  114 , which can be configured to abut up against a raised lip  146  located within the dead hinge section opening  123 . When the threaded flange  104  is screwed into the rear threaded section  106  of the receiver  101 , the dead hinge section  102  can be placed against, and connected to the receiver  101 . The threaded flange  104  can also comprise slots  107 , which can be used to facilitate turning the threaded flange  104 , in order to screw it into the rear threaded section of the receiver  101 . The force of the head  114  against the raised lip  146  can securely connect the dead hinge side  102  to the receiver  101 , according to an embodiment. 
         [0031]    In an embodiment, the dead hinge section  102  can also comprise a slot  125  configured to receive a locking button assembly  105  that can extend through the dead hinge section  102 . A button  150 , comprising the locking button assembly  105  can extend through the slot  125  comprising the dead hinge section  102  and pass out of the opposite side (not shown in  FIG. 1A ) of the dead hinge section  102  so that it can be pushed by a user&#39;s thumb or finger. Pressing the button  150  into the slot  125 , can thus actuate the locking button assembly  105 . In an embodiment, the locking button assembly  105  can be spring-loaded through use of a locking button spring  115  in order to hold the button  150  in a locked position until the button  150  is pressed into the slot  125  and into an unlocked position. In an embodiment, the button  150  can be pressed in order to allow the live hinge section  112  to pivot about the dead hinge section  102  between an open position and a closed position using a hinged joint comprised of a hinge pivot  138  and two hinge tabs  134  joined by a hinge pin  139 . In an embodiment, the hinged joint can comprise one or more stays configure to hold the stock in either an open position or a closed position until a force sufficient to overcome the stay is applied to the hinged joint. 
         [0032]    In an embodiment, the locking button assembly  105  can further comprise a button cover  151 , which can be used to retain the remaining parts of the locking button assembly  105  through the use of a setscrew  118 , which can connect the locking button assembly  105  to the dead hinge section  102 . In an embodiment, the locking button assembly  105  can comprise a tab  108 , which can extend through the slot  125  and into the dead hinge section opening  123  comprising the dead hinge section  102 . This tab  108  can act as a stay, which can be configured to prevent the bolt carrier assembly  180  from falling out of the receiver  101  when the folding stock adapter  100  is in an open (folded) position. This tab  108  can be configured to move into the slot when the folding stock adapter  100  is in a closed position thus allowing the action spring and buffer unobstructed access to the bolt carrier extension  170  and bolt carrier assembly  180 . 
         [0033]    In an embodiment, the live hinge section  112  can comprise a first live hinge side  130  and a second live hinge side  131 . When the folding stock adapter  100  is in a closed position, the first live hinge side  130  of the live hinge section  112  can be placed against the second dead hinge side  122  of the dead hinge section  102 . The live hinge section  112  can further comprise two hinge tabs  134 , which can be connected to the hinge pivot  138  comprising the dead hinge section  102 . 
         [0034]    In an embodiment, the live hinge section  112  can also comprise an aligning indentation  133  which can match the aligning indentation  163  located on the rear section of the receiver  101 . This aligning indentation  133  can be used to align the stock (not shown in  FIG. 1A ) against the second live hinge side  131  by using an aligning tab on the stock (not shown in  FIG. 1A ), which can be configured to fit within the aligning indentation  133 . A rifle can be connected to the live hinge section  112  by screwing a standard receiver extension comprising the rifle stock into a threaded circular receiver hole  132 , which can be configured to allow an action spring and buffer (not pictured) to contact the bolt carrier extension  170 . (Note that although threaded connections are used to connect the dead hinge  102  to the receiver  101  and the stock of the weapon to the live hinge section  112 , various alternative types of connectors could be used to facilitate these connections.) The folding stock adapter can be configured so that when the dead hinge side  102  is connected to rear threaded section  106  of the receiver  101  by the threaded flange  104 , and the live hinge section  112  is abutted against the dead hinge section  102 , thus forming a continuous opening from the receiver  101  to the receiver extension, which can allow the action spring and buffer (not shown in  FIG. 1A ) to contact the bolt carrier extension  170  in order to actuate the bolt carrier assembly  180 . The bolt carrier assembly  180 , comprising typical military-style assault rifles is actuated by the action spring and buffer, which are pushed backward by gas pressure produced by a cartridge when it is fired then moves forward when the gas pressure subsides. This back and forth, reciprocating motion allows the weapon to eject spent cartridges and chamber new ones thus preparing the weapon to re-fire with each cycle. 
         [0035]      FIG. 1B  is an exploded rear, top and side perspective view drawing of a bolt carrier assembly  180 , including a bolt carrier extension  170 , according to an embodiment. 
         [0036]    In an embodiment, the folding stock adapter  100  can also comprise a bolt carrier extension  170 , which can be connected to the bolt carrier assembly  180  thus extending its length. This extension in length can compensate for the length added to the rifle by the addition of the folding stock adapter  100  ensuring that the action spring and buffer (not shown in  FIG. 1B ) can still properly actuate the bolt carrier assembly  180 . In an embodiment, the bolt carrier extension  170  can comprise a tapered end  172  configured to fit within an opening  182  comprising the bolt carrier assembly  180 . The bolt carrier extension  170  can also comprise a head end  171  configured to contact, and be actuated by the action spring and buffer (not shown in  FIG. 1B ). The head end  171  can comprise one or more cutout sections  174 , the purpose and function of which will be described below. 
         [0037]      FIG. 1C  is a rear, top and side perspective view drawing of a bolt carrier assembly  180  connected to a bolt carrier extension  170  according to an embodiment. 
         [0038]    This view shows how the bolt carrier assembly  180  would appear if the tapered end  172  (not shown in  FIG. 1C ) of the bolt carrier extension  170  was to be placed into the opening  182  comprising the bolt carrier assembly  180  shown in  FIG. 1B . 
         [0039]      FIG. 2  is an exploded front, top and side perspective view drawing of a folding stock adapter  100  and a receiver  101  such as those commonly comprising many military-style assault rifles, according to an embodiment. 
         [0040]    In an embodiment, the first live hinge side  130  of the live hinge section  112  can comprise a locking tab  135  which can be configured to be received by the indentation  120  (shown in  FIG. 1A ) comprising the dead hinge section side  122 . When the folding stock adapter  100  is in a closed position, the locking tab  135  can be inserted into the indentation  120  and the tab retainer  520  (not shown in  FIG. 2 , but shown in  FIG. 5 ) comprising the locking button assembly  105  can be inserted into the locking tab hole  136  in order to lock the folding stock adapter  100  into a closed position. Likewise, the tab retainer  520  comprising the button  150  can be removed from the locking tab hole  136 , by pressing in the button  150 , in order to allow the folding stock adapter  100  to be placed into an open position thus allowing the stock to be folded against the receiver  101 . 
         [0041]    In an embodiment, the threaded circular receiver hole  132  can comprise a threaded hole  225 , configured to be connected to a buffer retaining pin  220 , which can prevent the buffer and action spring (not shown in  FIG. 2 ) from being accidentally removed from the receiver extension (not shown in  FIG. 2 ). The cutout sections  174  (shown in  FIG. 1B ) comprising the head end  171  of the bolt carrier extension  170  can be configured to allow the bolt carrier extension  170  to pass over the buffer retaining pin  220  so as to facilitate contact with the buffer and action spring. 
         [0042]      FIG. 3  is a perspective rear, side, and bottom view drawing of a folding stock adapter  100  in a closed position connected to a receiver  101  such as those commonly comprising many military-style assault rifles, according to an embodiment. 
         [0043]    In an embodiment, the folding stock adapter  100  can be placed into a closed position wherein two hinge tabs  134  can be rotated about the hinge pivot  138 , connected by a hinge pin  139  (not visible in  FIG. 3 ), in order to place the live hinge section  112  against the dead hinge section  102 . In this closed position, the receiver  101  can be placed into alignment with the stock (not pictured in  FIG. 3 ) allowing the bolt carrier extension  170  to pass through the threaded circular receiver hole  132 , the circular flange hole  141  (see  FIG. 1A ), and the circular dead hinge section opening  123  (see  FIG. 1A ). When the folding stock adapter  100  is in this closed position, the receiver  101  and stock are lined up in a functional position and the weapon can be fired normally. 
         [0044]      FIG. 4  is a perspective rear, side, and top view drawing of a folding stock adapter  100  in a closed position connected to a receiver  101  such as those commonly comprising many military-style assault rifles, according to an embodiment. 
         [0045]    In an embodiment, the folding stock adapter  100  can be in a closed position wherein the locking tab  135  (not pictured in  FIG. 4 ) comprising the live hinge section  112  can be inserted into the indentation  120  (not pictured in  FIG. 4 ) comprising the dead hinge section  102  so that the dead hinge section  102  and the live hinge section  112  can be held together to allow the weapon to be fired. The button  150  can be pressed to release the live hinge section  112  and allow the stock (not viewable in  FIG. 4 ) to be folded against the receiver  101 . The dead hinge section  102  can comprise a raised shroud  126  which can help prevent the accidental activation of the button  150 . 
         [0046]      FIG. 5  is a perspective rear, side, and top view drawing of a folding stock adapter  100  connected to a receiver  101  such as those commonly comprising many military-style assault rifles, according to an embodiment. 
         [0047]    In an embodiment, the folding stock adapter  100  can be in an open position wherein the button  150  has been pressed and the locking tab  135  on the live hinge section  112  has been released from the dead hinge section  102 . The dead hinge section  102  remains attached to the receiver  101  while the live hinge section  112  is free to rotate about the hinge assembly  505 . As the live hinge section  112  is attached to the stock (not shown in  FIG. 5 ), the stock can also rotate around to one side of the receiver  101 , allowing the overall length of the weapon to be reduced by nearly the entire length of the stock. 
         [0048]      FIG. 6A  is a top and side perspective view drawing of a military-style assault rifle  600  comprising a folding stock adapter  100  in a closed (fully functional) position, according to an embodiment. The buffer and action spring can be located within the receiver extension  610  comprising the stock  620 . 
         [0049]      FIG. 6B  is a top and side perspective view drawing of a military-style assault rifle  600 , comprising a folding stock adapter  100 , in an open (folded) position, according to an embodiment. This drawing, when viewed in comparison to  FIG. 6A , clearly illustrates the reduction of the rifle&#39;s  600  overall length, when the stock is in the folded position allowed by the folding stock adapter  100 . 
         [0050]      FIG. 7A  is a side, bottom and rear perspective view drawing of a folding stock adapter  100  in a closed position, according to an embodiment. 
         [0051]      FIG. 7B  is a side, top and rear perspective view drawing of a folding stock adapter  100 , in an open position, according to an embodiment. 
         [0052]      FIGS. 7A and 7B  clearly depict the parts that comprise the present folding stock adapter  100  absent any rifle parts to be connected to the adapter. In particular,  FIG. 7B  clearly shows the tab retainer  520  located within the indentation  120 , which can retain the locking tab  135 . 
         [0053]      FIG. 8  is an exploded side and rear perspective view drawing of a standard rifle stock  820  (prior art), receiver extension  810  (prior art), action spring  840  (prior art), buffer  830  (prior art), bolt carrier extension  170 , and live hinge section  112 , according to an embodiment. 
         [0054]    Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the invention, which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention.