Firearm Attachment Assembly for Ambidextrous Use

The present disclosure relates generally to accessories for firearms, more specifically, to a modular attachment block for firearm accessories, and most specifically to a folding gun stock for ambidextrous use.

Firearms, such as a rifle or a shotgun, typically include a receiver and a barrel attached to the forward end of the receiver. The receiver commonly houses the primary components of the firearm such as the firing mechanism and the firing chamber. In some modern firearms, the receiver can be further divided into an “upper receiver” and a “lower receiver,” with the lower receiver being the part that encloses the primary components of the firearm. The upper receiver in these firearms typically houses the bolt and connects to the barrel. Many firearms, particularly rifles and shotguns, include a stock or buttstock extending rearwardly from the receiver. The buttstock is the end of the firearm an operator braces himself against, typically in the shoulder area, to steady the firearm prior to and during firing events, to allow the operator to absorb recoil energy and to stabilize the firearm to ensure accuracy during firing.

While the buttstock is an important feature of the firearm, it can also add significant weight to the firearm, making certain firearms less desirable to use in certain scenarios. Further, the buttstock can significantly increase the overall length of the firearm thereby posing spatial limitations on transport and use. To reduce weight added by the buttstock, many modern rifle designs use a synthetic or composite material to form the buttstock, which is significantly lighter than hardwood.

The length that a buttstock adds to the firearm remains problematic. To address this issue, various folding and telescoping buttstocks have been made to allow for temporary reduction in the overall length of the firearm. Many telescoping buttstocks, however, reduce the overall length by only a few inches, which may not be sufficient for certain military usage and may still pose issues with handling and transport. While some folding buttstocks increase the amount of length reduction when folded, the designs are typically limited to either left-hand or right-hand folding and can be bulkier and heavier than the telescoping options. Further, the actual folding action may be cumbersome and time consuming, significantly reducing the ability of an operator to quickly fold or deploy the buttstock when needed in the field.

Firearm buttstocks also require a high level of durability to be able to withstand the rough handling firearms are typically exposed too, particularly in military and law enforcement uses. For instance, some U.S. military specifications require firearms, including an attached buttstock, to survive repeated drops from five feet high directly onto a concrete or other type of hard surface. These drop tests typically involve repeatedly dropping the firearm onto the hard surface at different angles to test the durability of specific components of the firearm, e.g., the buttstock, while ensuring overall structural integrity is maintained throughout the test. However, the structural durability of the firearm and attachments must be balanced against the continuing need to reduce the overall weight of the firearm, particularly in the context of military use where added weight to the firearm increase the total load a soldier must carry into the field.

Further improvements are needed to address all of the aforesaid problems.

The invention disclosed herein relates to an attachment platform that can mount firearm accessories to a firearm and provide for both right-hand and left-hand folding (hereafter “ambidextrous folding”) for a buttstock. In some embodiments, an ambidextrous folding gun stock assembly is disclosed. The ambidextrous folding gun stock assembly includes an attachment block, a hinge block, and a latching mechanism. The attachment block has a distal side defining a means for removably engaging a firearm receiver, and a proximal side that defines an engagement interface with a transverse engagement channel. A pair of hinge pin holes are defined at both ends of the transverse engagement channel. The hinge block removably attaches to the attachment block. The hinge block includes a stock receiving side and a latching side defining a latching interface. The latching interface includes a transverse latching channel and a pair of pin holes formed at opposite ends of the channel. The latching mechanism extends through the transverse latching channel and is partially retained therein at one end of the channel by a set pin. A removable hinge pin removably attaches the hinge block to the attachment block and extends through concentrically aligned pin holes of each component piece.

Each pair of hinge pin holes of the attachment block defines an axis of rotation for the hinge block when assembled. The axis of rotation defined by the hinge pin holes is substantially perpendicular to the direction of the transverse engagement channel. In preferred embodiments, the engagement interface is bilaterally symmetrical. Similarly, the second pair of pin holes for the hinge block defines another axis of rotation. The latching interface of the hinge block is preferably bilaterally symmetrical about this other axis of rotation.

In preferred embodiments, the transverse engagement channel of the attachment block includes a planar surface disposed between two angled surfaces defined at each end of the channel. Preferably, each angled surface is disposed between one pair of the hinge pin holes so that the pin holes are perpendicular to the channel. The body of the attachment block includes a first hook catch and a second hook catch formed in a thickness of the body. Preferably, each hook catch is formed in the body between the distal side and one of the angled surfaces formed on the proximal side. The latching mechanism is designed to engage one of the hook catches when the assembly is in a deployed position. The opposite end of the latching mechanism is designed to rotationally engage one of the angled surfaces when the assembly is in the folded position.

In some embodiments, the latching mechanism has an elongated body extending between apertures defined at either end of the body. Each of the apertures is preferably horizontally elongated or slotted, where the length of the slots defines the maximum horizontal distance the latching mechanism is movable across the hinge block. Preferably, the elongated body of the latching mechanism is greater than a horizontal length of the transverse engagement channel. A first end of the elongated body may include a hook configured to removably engage one of the hook catches and a second end, opposite the first end, may include a curved surface designed to rotatably engage one of the angled surfaces of the attachment block. Movement of the latching mechanism across the hinge block detaches the hook from the hook catch thereby allowing the hinge block to rotate about the hinge pin connecting the hinge block to the attachment block. Rotation may continue until the hinge block has been rotated substantially 180 degrees to the folded position. When folded, the curved end of the latching mechanism engages a portion of the transverse engagement channel, e.g., one of the angled surfaces, to generate a resistance force thereby securing the assembly in the folded position.

In further embodiments, the invention may relate only to a hinge block assembly. The hinge block assembly includes the hinge block and the latching mechanism attached to the hinge block. A latching side of the hinge block defines a transverse latching channel that partially encloses the latching mechanism therein. A pair of pin holes are defined at either end of the transverse latching channel. One set of the pin holes defines an axis of rotation about which the latching side is bilaterally symmetrical.

Similarly, in other embodiments the invention may relate only to the attachment block. The attachment block has a proximal side and a distal side. The distal side defines a means for removably attaching the block to a firearm receiver. The proximal side defines a mounting interface that includes a transverse engagement channel with a pair of pin holes defined at both ends thereof. The mounting interface is bilaterally symmetrical about a central axis. In some embodiments, the transverse engagement channel includes a planar surface disposed between two angled surfaces.

These and other features of the disclosed invention will become apparent to those skilled in the art in view of the following detailed disclosure.

The following disclosure provides exemplary embodiments of a foldable firearm accessory attachment platform. In particular, the inventive concepts disclosed herein relate to an attachment assembly that can removably attach various firearm accessories, such as a buttstock, to a modern firearm. According to aspects of the inventive concepts disclosed herein, some embodiments of the invention may include an attachment block directly engaged to the firearm receiver. The attachment block may thereafter be used as a platform to removably attach various firearm accessories, such as a butterfly trigger assembly. In other embodiments, the invention may include an attachment block and a hinge block rotatably engaged thereto. The hinge block may rotatably attach a buttstock or other accessories to the rear of the firearm.

Throughout the following disclosure, terms such as “firearm” and “gun” may be used interchangeably and it should be understood that use of these terms is meant to refer to the broad categories of rifles and shotguns for both military and civilian use. Further, directional terms such as forward, rear, distal, proximal, etc. may be used throughout the disclosure to aid the reader in understanding the invention. These terms are made in reference to a standard firearm being handled normally so that the “forward” or “distal” end is the end having the barrel. In contrast, the “proximal” end would be the opposite end of the firearm having the buttstock. Furthermore, it should be understood that reference to a longitudinal axis is meant to refer to the imaginary axis defined by the barrel and, unless otherwise noted, reference to a “transverse” direction is meant to describe a direction with regard to the normal longitudinal axis defined by the barrel. As such, a “transverse” feature is to be understood as a feature perpendicular to the longitudinal axis of the gun. It should also be understood that left-handed and right-handed is used in reference to a standard firearm handled normally by an operator so that a “left-handed” folding action results in folding occurring down the left-side of the firearm leaving the trigger assembly exposed from the right-side.

is a perspective view of one embodiment of an ambidextrous folding gun stock assemblyaccording to the present invention. The ambidextrous folding gun stock assemblyincludes an attachment blockand a hinge blockhaving a latching mechanismretained therein. A buttstockcan be removably attached to the hinge block. Alternatively, many other types of firearm accessories may be removably attached to the hinge blockor may be directly attached to the attachment block, depending on the requirements of the firearm and the accessory to be mounted.

Note, for ease of illustration and to ensure the focus remains on the inventive ambidextrous folding gun stock assembly, the firearm to which the assembly would attach is not illustrated. It should be understood that the firearm attaches to the distal side of the attachment block, as explained in more detail below.

The ambidextrous folding gun stock assemblyillustrated inis configured for a left-handed folding action, which leaves the trigger assembly exposed for a right-handed shooter. In contrast,is a perspective view of the ambidextrous folding gun stock assemblyconfigured for a right-handed folding action, leaving the trigger assembly exposed for a left-handed shooter.illustrate the same embodiment of the ambidextrous folding gun stock assembly, with the only difference being the direction in which the folding action will occur. As will be explained in further detail below, the hinge blockis engineered so that the latching mechanismcan engage either the left side or the right side of the attachment block, depending on need of the operator, e.g., right-handed shooter versus left-handed shooter, to allow for an ambidextrous folding action.

is a side view of an embodiment of the ambidextrous folding gun stock assembly. The ambidextrous folding gun stock assemblyis illustrated as being in a deployed position for a right-handed shooter. The ambidextrous folding gun stock assemblycan fold down the left side of the firearm, allowing a right-handed shooter to continue operation of the firearm in either the folded or deployed positions. The same ambidextrous folding gun stock assemblycan be configured for a left-handed shooter so that the folding action occurs down the right side of the firearm, as discussed in more detail herein.

is a perspective view of a distal side of an embodiment of the attachment blockaccording to the present invention.is a perspective view of a proximal side of the attachment blockfrom. The attachment blockillustrated inhas been removed from the other components of the ambidextrous folding gun stock assembly. The attachment blockhas a distal side(e.g.,) distinct from its proximal side(e.g.,). A bodyconnects the distal sideand the proximal side. A means for removably attaching the attachment blockto a firearm receiver is formed on the distal side. In some embodiments, the firearm receiver attachment means may include a hookand a lower locking pin channel. The locking pin channelextends transversely through the body. The hookmay be integrally formed with and extending upwards from the distal side. The hookis configured to engage a pocket defined in the firearm receiver. Note, the exact profile of the hookmay vary depending on the specific firearm to which the assemblyis designed to mount. When the hookis properly engaged with a pocket on the firearm receiver, the locking pin channelwill align between opposing retention apertures on the firearm receiver and a removable retention pin may be installed through the locking pin channelto secure the attachment blockto the firearm receiver. An example of this alignment and engagement of the attachment blockto a firearm receiver can be found in, where the attachment blockis utilized to attach a butterfly trigger assembly to the firearm. The retention pin may be press fit through the locking pin channelto allow for easy and convenient installment or removal of the attachment blockto the firearm receiver. Engagement of the attachment blockto a firearm receiver is independent of the accessory attached to the attachment block. Thus, the interaction between the attachment blockand the firearm receiver illustrated inis the same interaction that would be found if, for example, the hinge blockwere attached thereto instead of to the butterfly trigger assembly.

The distal sidealso defines a stopping surface. The stopping surfaceis designed as a backstop for the internal buffer cartridge that receives the bolt as it recoils backwards under normal firing conditions. Upon discharge of the firearm, the bolt recoils backwards and contacts a spring contained within a buffer cartridge. The stopping surfaceacts as the backstop for the buffer cartridge and prevents the buffer cartridge from being blown out of the rearward end of the firearm. The spring absorbs the recoil energy and thereafter moves the bolt forward to chamber the next round. The stopping surfaceensures that a firearm with the attachment blockmounted thereto remains operational regardless of the accessory, if any, engaged to the attachment block and regardless of whether the assembly is in the folded or deployed position.

The proximal sideof the attachment blockdefines an engagement interfacethat is bilaterally symmetrical about a central axis extending from the top end to the bottom end of the proximal side. The bilateral symmetry of the proximal sideadds to ambidextrous folding capability of the folding gun stock assembly. The engagement interfaceincludes a transverse engagement channeland two pairs of hinge pin holesA,B defined at either end of the channel. Preferably, the two pairs of hinge pin holesA andB are oriented perpendicular to the direction of the transverse engagement channel. Each pair of hinge pin holesA,B includes an upperand a lowerpin hole concentrically aligned with one another with the transverse engagement channelextending therebetween.

In some preferred embodiments, the transverse engagement channelincludes a planar surfacedisposed between two angled surfaces,. Preferably, each angled surface,is aligned between an upperand a lowerpin hole for each pair of pin holesA,B. In some embodiments, each angled surface,acts as a detent surface, in cooperation with the latching mechanism, to secure the ambidextrous folding gun stock assemblyin a folded position. The attachment blockalso includes a pair of hook catchesdefined in the bodybetween the distal sideand the proximal side. Preferably, each hook catchis defined between the distal sideand one of the angled surface,of the proximal side. Each hook catchis designed to engage a portion of the latching mechanismto secure the ambidextrous folding gun stock assemblyin the deployed position, as shown in.

In some embodiments of the attachment block, the upper surfacemay include an optics channel. The optics channelis engineered for the removable engagement of an optics assembly, such as assemblyillustrated inand described below. In preferred embodiments, the optics channelextends through the upper surfaceand opens into the distal side. A drain channelmay align with the optics channelto allow buildup and other debris to be easily cleaned from the optics channel by an operator.

is a perspective view of a front end of an embodiment of the hinge blockaccording to the present invention.is a perspective view of a back end of the hinge blockshown in. The hinge blockillustrated inis shown isolated from the other components of the ambidextrous folding gun stock assemblyfor ease of illustration and clarity. The hinge blockhas a latching sideand a stock receiving side. The stock receiving sideincludes a means for removably engaging a buttstock or other firearm accessory type. In some embodiments, the buttstock engagement means includes an internally threaded apertureconfigured to threadably engage a buttstock such as buttstock. The threaded aperturemay extend fully through the hinge blockfrom the stock receiving sideto the latching sideto further reduce the weight of hinge blockand allow for easy cleaning of the block as needed.

The latching sidedefines a latching interfacethat will rotatably contact the engagement interfaceof the attachment blockwhen in a deployed position. The latching interfaceincludes a transverse latching channelwith a pair of pin holes disposed at either end of the channel. Preferably, a pair of set pin holesare defined at one end of the transverse latching channeland a pair of hinge pin holesare defined at the opposite end of the channel. The pair of set pin holesare preferably designed to receive a press-fit set pin so as to be permanently set therein (e.g., set pinshown in). In contrast, the pair of hinge pin holesare preferably designed to removably receive a hinge pin in clearance fit (e.g., hinge pinshown in). The transverse latching channelis sized to house the latching mechanism, as described in more detail below.

The transverse latching channelis formed between a first railand a second rail. Each pin hole in the pair of set pin holesand each pin hole in the pair of hinge pin holesis defined through one of the first railand the second rail. The pin holes,are perpendicular to the direction of the transverse latching channel. Further, each hole in each pair of pin holesandis concentrically aligned with the opposing hole from that pair of holesor, with the transverse latching channelextending therebetween. Preferably, the first railand the second railinclude a rotational stopping surfaceformed proximate to the set pin holes. The rotational stopping surfacesare thickened portions of the first and second rails,formed to rotatably contact a portion of the planar surfaceto limit the maximum rotation of the hinge blockin the direction the attachment blockwhen the ambidextrous folding gun stock assemblyis in a deployed position. The rotational stopping surfacesalso differentiate the set pin holesfrom the hinge pin holesbecause the rotational stopping surfacesare only formed on the set pin side of the transverse latching channel. It is preferred that the hinge pin holesbe configured to receive the hinge pinin a clearance fit engagement so that the hinge blockmay be quickly detached from the attachment blockto switch the configuration from left-handed to right-handed (or vice versa). In contrast, the set pin holesreceive the set pinin a press fit engagement to ensure the latching mechanismis at least partially retained in the transverse latching channelregardless of whether the hinge blockis attached to the attachment block. In this manner, the latching mechanismis also at all times at least partially engaged to the hinge block.

The pair of hinge pin holesdefine an axis of rotation about which the hinge blockcan rotate when installed to the attachment blockto form the ambidextrous folding gun stock assembly. In preferred embodiments, the hinge blockcan rotate around the axis defined by the hinge pin holessubstantially 180 degrees off the engagement interfaceof the attachment block. The latching interfaceis also designed to be bilaterally symmetrical about the rotational axis of the hinge pin holes. That is, the hinge block can be flipped or inverted substantially 180 degrees about the axis of the hinge pin holesresulting in a mirror image of the latching interface. The bilateral symmetry of the latching interfacedefined by the axis of the hinge pin holesaids in making the folding gun stock assemblyambidextrous for both left-handed and right-handed folding actions, as explained in more detail below.

is a side view of an embodiment of a latching mechanism, isolated from the hinge block, according to aspects of the present invention.is a cross-sectional view of the latching mechanism, taken along lines C-C of. The latching mechanismincludes a hookformed at one end and a curved camformed at an end opposite the hook. The hookand the curved camare integrally connected by an elongated body. The curved camis oriented in the opposite direction of the hook. The elongated bodyis preferably longer than a horizontal length of the transverse latching channelso that the latching mechanismcan move therethrough for purposes of engaging and disengaging the attachment block.

A first apertureis defined through the elongated bodyproximate to the hook. Similarly, a second apertureis defined through the elongated bodyat the opposite end proximate to the curved cam. Each of the first apertureand the second apertureare slotted or horizontally elongated. As such, these features will be referred to as the first slotand the second slothereafter. The length of each of the first slotand the second slotdefines the maximum horizontal distance the latching mechanismis movable across the transverse latching channel. The horizontal movement of the latching mechanismis designed to lock and unlock the ambidextrous folding gun stock assemblyin a deployed position and rotatably secure and unsecure the hinge blockin a folded position.

An internal channelis defined within the elongated bodyand extends from the first slottowards the second slot. A drain channelconnects one end of the internal channelto the second slotand provides a convenient escape path for any buildup that may need to be cleaned out from the latching mechanism. A compression spring, e.g., see, is housed in the internal channel. When the latching mechanismis installed in the hinge block, the springis fixed at one end of the internal channelin the first slotand extends towards the second slot. The springterminates at the drain channel, which has a diameter less than the diameter of the internal channel. The springprovides a compressive force to secure the hookin engagement with a hook catchwhen the hinge blockis in the deployed position and to engage the curved camagainst the angled surfaceorwhen the hinge blockis in the folded position. The springis retained in internal channelby set pinextending through the first slotwhen the latching mechanismis installed in the hinge block.

is a top-down cross sectional view of an embodiment of the ambidextrous folding gun stock assemblyin a deployed position.is taken along section line A-A marked in. A set pinextends through the pair of set pin holesand the first slotto fixedly attach the latching mechanismto the hinge blockat one end of the transverse latching channel. The set pinalso secures the springwithin the internal channeland is fixed partially in the first slot. At the opposite end, a removable hinge pinextends through one of the pairs of the pin holesA orB, through the hinge pin holesand through the second slotto rotatably attach the hinge blockto the attachment block. The hookremovably engages the hook catchdefined in the bodyof the attachment blockto lock the ambidextrous folding gun stock assemblyin the deployed position, as shown in.

To effectuate the folding action, an operator first applies a force to the latching mechanismat the curved camin the direction of arrow Y shown in. The force applied to the latching mechanismin direction Y compresses the springallowing the latching mechanismto move in the same direction in which the force is applied. The set pinand the hinge pinwill engage an inner edge of the first slotand second slot, respectively, to limit the distance the latching mechanismcan move horizontally. When the force Y is applied to the latching mechanism, the hookdisengages the hook catchallowing the hinge blockto rotate about the axis defined by the hinge pin. Once the hookhas disengaged from the hook catch, the force Y may be removed from the latching mechanismallowing it to return to its original position on the hinge block.

To complete folding of the gun stock assembly, a rotational force is applied to the hinge blockin the direction of arrow X shown in, causing the hinge blockto rotate about the hinge pinand away from the attachment block. As the hinge blockcontinues to rotate about the hinge pin, the curved camcomes into contact with the one of the angled surfaces,which applies a counter force to the latching mechanismagain compressing the spring. The hinge blockcontinues to rotate in direction X until the curved camovercomes the angled surfaceorand the compressive force applied to the springis relieved. The latching mechanismmoves back to its original positioning in the hinge blockand the curved camis maintained in frictional engagement with the angled surfaceor. The frictional engagement between the curved camand the angled surfaceorsecures the assemblyin the folded position.

is a top-down cross sectional view of an embodiment of the ambidextrous folding gun stock assemblyin a folded position.is the same cross-sectional view as, but shows the assembly in a folded position with the hinge block rotated clockwise 180 degrees. The curved camengages the angled surfacesorto secure the gun stock assemblyin the folded position. The hinge blockis attached to one side of the attachment blockthrough either pin holesA or pin holesB so that the hinge blockcan rotate about the hinge pinbetween the deployed position (e.g.,) and the folded position (e.g.,). To ensure the rotational capability is achieved, the second slotis concentrically aligned with the hinge pin holesin the hinge blockand the same hinge pin holesare thereafter concentrically aligned with one of the pairs of pin holesA orB prior to installation of the removable hinge pin. The removable hinge pindefines the axis of rotation and securely attaches the hinge blockto the attachment block.

To re-deploy the folding gun stock assembly, an operator applies a rotational force to the hinge blockin the direction of arrow Z. The hinge blockbegins to rotate about the hinge pinand the curved camengages the angled surfaceorto begin compressing the springand move the latching mechanismacross the transverse latching channel. An operator continues application of the rotational force Z until the curved camovercomes the angled surfaceorrelieving the compression of the spring. Rotation of the hinge blockcontinues until it is substantially in line with the longitudinal axis of the firearm. At this point, an operator again applies a compressive force Y (e.g.,) to the curved camend of the latching mechanismto move the latching mechanism across the transverse latching channelso that the hookcan re-engage one of the hook catches. The force is then removed causing the latching mechanismto return to its original position with the hooksecurely engaged with a hook catch.

In, the ambidextrous folding gun stock assemblyis configured for a right-handed operator. That is, the ambidextrous folding gun stock assemblyas depicted folds along the left side of the firearm so that the right-handed operator can access the trigger from the right side thereby ensuring the firearm remains operational in both the folded and the deployed positions. The folding and deploying actions can be accomplished with one hand, e.g., the left hand in the depicted configuration, with the other hand free to continue holding and firing the firearm.

In some preferred embodiments, the springhas a spring rate of at least 8 pounds of force (“lbf”), which is sufficient to secure the latching mechanismin both the folded and deployed positions. Along similar lines, the angle for each angled surface,is preferably about 20 degrees, defined from the planar surfaceand extending toward the distal side. A springhaving a spring rate of at least 8 pounds of force and a 20 degree angle for each angled surface,has been determined to provide adequate retention torque to lock the hinge blockin the folded position while requiring a minimal amount of force to overcome the retention torque for rapid deployment from the folded position. Further, an 8 lbf spring rate for the springhas been determined to be optimal to ensure the ambidextrous folding gun stock assemblyis secured in the deployed position while requiring a minimal amount of force to activate the latching mechanismto begin the folding action.

is a series of perspective views of an embodiment of the ambidextrous folding gun stockillustrating the salient steps for switching from a right-handed configuration to a left-handed configuration, according to the present invention. As used herein, it should be understood that a right-handed configuration is meant to refer to the folding gun stock assemblybeing configured for a right-handed operator so that the hinge blockis folded down the left side of the firearm to leave the trigger assembly accessible from the right side. Similarly, the left-handed configuration is meant to refer to the folding gun stock assemblybeing configured for a left-handed operator so that the hinge blockis folded down the right side of the firearm to leave the trigger assembly accessible from the left side.

The firearm has been omitted from this series of images infor purposes of clarity and to ensure the focus remains on the inventive assembly. Similarly, through several of the illustrated steps, the buttstockhas been purposefully omitted for clarity purposes.

Starting at the top left side of the page, Stepillustrates a portion of the ambidextrous folding gun stock assemblyas deployed in a right-handed configuration. To swap the folding gun stock assemblyinto a left-handed configuration, the operator at Stepremoves the hinge pinfrom the assemblyto detach the hinge blockfrom the attachment block. For descriptive purposes only, the left pair of pin holes on the attachment blockmay be identified as pin holesA and the right pair of pin holes on the attachment blockmay be identified as pin holesB. As illustrated for this example, the hinge pinis removed from the pair of pin holesA on the left side of the attachment block. When the assemblyis installed on a firearm, the attachment blockremains attached thereto throughout the ambidextrous flipping operation. A small punch or other type of durable cylindrical tool may be used to remove the hinge pinfrom the assembly. The latching mechanismis retained in the hinge blockby the set pin, which is not removed during the process.

At Step, the hinge blockis flipped or inverted 180 degrees around the axis defined by the pair of hinge pin holesso that the hookis oriented in a direction opposite from its original direction (e.g., right versus left). Once the hinge blockis inverted, at Stepthe hinge block is realigned in the transverse engagement channelso that the pair of hinge pin holesand the second slotare aligned between the pair of pin holesB on the right side of the attachment block. The hookmay also be positioned to engage a hook catchduring the realignment of the hinge blockwith the attachment block. The hinge pinis reinstalled through the concentrically aligned pin holesB,andto rotatably secure the hinge blockto the right side of the attachment block.

The bilateral symmetry of the engagement interfaceensures that the hinge blockcan be readily attached to the attachment blockregardless of whether it is in a right-handed or left-handed configuration. Further, by designing the latching interfaceto be bilaterally symmetrical about the rotational axis defined by the hinge pin holes, an operator can quickly switch between the right-handed and left-handed configurations by removing the hinge pinand inverting the hinge blockprior to reinstalling the hinge pin on the opposite side. Operation of the ambidextrous folding gun stock assemblyis the same regardless of whether it is installed in a right-handed or left-handed configuration, with the only difference being the direction in which the folding action takes place.

Once the hinge blockhas been inverted and reinstalled on the opposite side of the attachment block, Steprequires flipping the orientation of the buttstock. To effectuate this flip of the buttstock, an operator can loosen a removable locking ringinstalled with the buttstockso that the buttstock can be rotated substantially 180 degrees about the longitudinal firearm axis. The operator simply tightens the locking ringonce the buttstockis properly oriented thereby locking the buttstock in position.

is a perspective view of a portion of an ambidextrous folding gun stock assemblyaccording to one embodiment of the present invention. The ambidextrous folding gun stock assemblymay include an adjustable sight optic assembly.illustrates the optic assemblyin stowed position.is a perspective view of a portion of the ambidextrous folding gun stock assemblywith the optic assemblyin a deployed position. The optic assemblyincludes a sight posthaving a plurality of notchesdefined along the vertical length of the post. A windage adjustment assemblyis formed at the top end of the sight postand includes an adjustment knobconfigured to incrementally move a sighthorizontally across the assembly.

Preferably, the optic assemblyis removably installed in the optics channeldefined through the upper surfaceof the bodyof the attachment block. A sight lockis retained in the bodyproximate the upper surfaceand extends partially through the optic channelto engage a portion of the sight opticto provide incremental adjustment thereof.is a magnified cross-sectional view of a portion of the attachment blockhaving an optic assemblyinstalled therein.is taken along section lines B-B marked in. The sight postextends through the optics channeldefined through the top surfaceof the attachment block. The sight lockincludes a spring loaded locking tabwhich extends partially into the optics channelto engage one of the plurality of notchesdefined along the vertical length of the sight post. To adjust the sight optic, an operator would depress the sight lockso the spring loaded locking tabdisengages from the sight postallowing vertical adjustment thereof. Once the operator has set the sight postto the desired height, the sight lockis released so the spring loaded locking tabcan re-engage one of the notchesalong the sight postto lock the post at the set height.

Each of the plurality of incremental notchesallows for the incremental vertical adjustment of the optic assemblycorresponding to a downrange distance. Preferably, the plurality of notchescorrespond to a downrange distance between 0 meters to 20 meters thereby allowing the operator to quickly adjust the sight opticfor accurate shooting between 0 and 20 meters using only the included metal sights. The windage adjustment assemblyis preferably adjustable between (+) 6 and (−) 6 millimeters to provide for a variety of incremental adjustments accounting for present windage.

is a partial perspective view of one embodiment of an attachment blockused to mount a firearm accessory other than a foldable buttstock, such as a butterfly trigger assembly. To mount an alternative firearm accessory which does not require a folding action, an operator will only need the attachment block. The attachment blockengages the firearm receiver, as described above, by engaging the hookin a pocketdefined in the firearm receiver. Similarly, the lower locking pin channelis aligned between pin aperturesformed on the receiverand a pinis installed therethrough to secure the attachment blockto the firearm receiver.

Once the attachment blockis installed to the firearm receiver, two set pinscan be used to secure an external firearm accessory to the engagement interface. As shown, a butterfly trigger assemblyis mounted to the attachment blockusing the two set pins. Each set pinwill extend through one pair of the pin holesA,B and through a portion of the accessory, e.g., butterfly trigger assembly, to secure the accessory to the engagement interface.

While the invention has been described with regard to an ambidextrous folding gun stock assembly, the attachment block can also serve as a mounting interface for removably mounting a firearm to a vehicle or other type of firing station. In such embodiments, the mounting interface on the vehicle or firing station may provide the mechanical linkage to activate the trigger assembly while the attachment block provides an easy and convenient interface to quickly mount and dismount the firearm, as needed. Such a configuration will allow an operator to quickly retrieve a mounted firearm to allow continued use of that firearm away from its initial mounted position, for instance in the case where the vehicle has become disabled.