Patent Publication Number: US-10788292-B2

Title: Quick-detach optics and accessory mounting system for firearms

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional application No. 62/478,503, filed Mar. 29, 2017, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The present disclosure relates to firearms, and, more particularly, to firearm accessory systems. 
     BACKGROUND 
     Standard mounting platforms have been used for attaching optics and other accessories to firearms. One such platform is the Picatinny rail, which includes a rail having multiple transverse slots. An accessory having a corresponding rail mount can be mounted to the firearm by sliding the accessory down the Picatinny rail and securely clamping the accessory to the rail, typically using clamps or screws. After optics accessories, such as telescopic sights or laser optics, are mounted to a firearm, the firearm is then zeroed by adjusting the optics so as to ensure that the point of aim of the optics is the point of impact. However, each time an accessory is detached from the firearm and later re-mounted, the firearm must be zeroed again. It would be desirable to provide a more effective accessory mounting system for firearms. 
     SUMMARY 
     In accordance with embodiments of the present invention, an accessory mounting system offering quick disconnect is provided. This mounting system can provide a true return-to-zero reattach. The mounting system includes a base, which is attached to the host platform, and a top mount onto which one or more accessories can be mounted. The base may be installed with a friction clamp and can remain attached to the host platform while the top mount can be removed and returned while keeping all optics and lasers mounted. The coupling of the base and top mount can provide sufficient precision such that the mounting system can retain zero upon reattach. The top mount may include one or more rail segments, which can enable the mounting of a laser system in conjunction with a top mounted optic, even when the firearm is used in conjunction with a gun shield. 
     In accordance with some embodiments, the mounting system can provide a low profile for an optics mount, which can enable the user to keep the user&#39;s head as low behind the gun shield as possible while still having a pass-through to utilize the standard iron sights. The system may be snag and sharp edge free so as not to interfere with the operating of the host weapon. The base of the mount may include a host connector portion which can enable the base to be left in place on the host system or can be easily removed as needed. The host connector portion may enable the base to be re-indexed to the same location upon re-mounting, and can be non-marring on the host system. 
     Systems and methods are provided for a firearm accessory mounting system. In a first embodiment, a firearm accessory mounting system comprises: a base assembly comprising: a host connector on a bottom side of the base assembly operable to couple with a firearm; and a mount connector on a top side of the base assembly; and a top mount comprising: a base connector on a bottom side of the top mount, the base connector being detachably coupled to the mount connector of the base assembly; and a rail connector on a top side of the top mount. 
     Still other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description, which describes embodiments illustrating various examples of the invention. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the spirit and the scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front perspective view of an accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 2A-2B  are left and right side plan views, respectively, of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 3A-3B  are top and bottom plan views, respectively, of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 4A-4B  are front and rear plan views, respectively, of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 5A-5B  are front and rear perspective views of a top mount of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 6A-6B  are left and right side plan views, respectively, of the top mount of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 7A-7B  are top and bottom plan views, respectively, of the top mount of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 8A-8B  are front and rear plan views, respectively, of the top mount of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 9A-9B  are front and rear perspective views of a base of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 10A-10B  are left and right side plan views, respectively, of the base of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 11A-11B  are top and bottom plan views, respectively, of the base of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIGS. 12A-12B  are front and rear plan views, respectively, of the base of the accessory mounting system, in accordance with embodiments of the present invention. 
         FIG. 13  is a right side view of the accessory mounting system mounted to a firearm, in accordance with embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying drawings that illustrate several embodiments of the present disclosure. It is to be understood that other embodiments may be utilized and system or process changes may be made without departing from the spirit and scope of the present disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the embodiments of the present invention is defined only by the claims of the issued patent. It is to be understood that drawings are not necessarily drawn to scale. 
     Various embodiments of the present disclosure provide improved firearm accessory mounting systems. These embodiments may enable accessories to be quickly mounted and detached, while maintaining precise calibration of the accessory. In contrast with conventional rail systems which are designed to enable the user to quickly detach an accessory from the rail, embodiments of the present invention are designed to enable the user to quickly detach the rail from the firearm, with the accessory still attached to the rail. Then, the rail with the attached accessory can then be quickly re-mounted onto the firearm. 
       FIG. 1  is a front perspective view of an accessory mounting system  100 , in accordance with embodiments of the present invention.  FIGS. 2A-2B  are left and right side plan views, respectively, of the system  100 ;  FIGS. 3A-3B  are top and bottom plan views, respectively, of the system  100 ; and  FIGS. 4A-4B  are front and rear plan views, respectively, of the system  100 . 
     The illustrated example system  100  is configured for use with a belt-fed, crew-serviced M2 machine gun, but other embodiments may be configured for use with other types of firearms. The system  100  includes a top mount  150  releasably attached to a base assembly  110 . 
       FIGS. 5A-5B  are front and rear perspective views of the top mount  150  of the accessory mounting system  100 , in accordance with embodiments of the present invention.  FIGS. 6A-6B  are left and right side plan views, respectively, of the top mount  150 ;  FIGS. 7A-7B  are top and bottom plan views, respectively, of the top mount  150 ; and  FIGS. 8A-8B  are front and rear plan views, respectively, of the top mount  150 . 
       FIGS. 9A-9B  are front and rear perspective views of the base  110  of the accessory mounting system  100 , in accordance with embodiments of the present invention.  FIGS. 10A-10B  are left and right side plan views, respectively, of the base  110 ;  FIGS. 11A-11B  are top and bottom plan views, respectively, of the base  110 ; and  FIGS. 12A-12B  are front and rear plan views, respectively, of the base  110 . 
       FIG. 13  is a right side view of the system  100  mounted to the receiver  1310  of a firearm  1300 , e.g., an M2 machine gun. 
     In the illustrated embodiment, the base  110  includes a host connector portion  112  operable to couple with the receiver component of the M2 machine gun and a mount connector portion  114  operable to couple with a corresponding base connector portion  154  of the top mount  150 . The top mount  150  includes an accessory mounting rail connector  152  to which an accessory can be attached. 
     The base assembly  110  comprises a body portion  916 , a left side member  910 , a right side member  920 , and a mount connector  114 . An upper end  914  of the left side member  910  and an upper end  924  of the right side member  920  are coupled to the body portion  916 . The lower ends of the side members  910 ,  920  comprise flange members  912 ,  922 , respectively. In the illustrated embodiment, the body portion  916 , left side member  910 , right side member  920 , and mount connector  114  are formed by a single metal component. Any suitable material may be used for the system  100 , such as, e.g., aluminum, steel, titanium, or alloys thereof. As can be seen in  FIG. 13 , the receiver  1310  of the firearm  1300  includes an upper cover  1320  having side portions  1322  which extend laterally beyond the sides of the main body portion of the receiver  1310 . In order to mount the base assembly  110  to the firearm  1300 , the base assembly  110  can be slid backwards along the top of the receiver  1310  so as to cause the flange members  912 ,  922  engage these side portions  1322 , thereby attaching the base assembly  110  to the firearm  1300 . 
     In order to provide a more secure coupling of the base assembly  110  to the firearm  1300 , clamping assemblies may be used in order to take up any slack in the coupling between the base assembly  110  and the receiver  1310 . As shown in  FIGS. 9A-9B , in the illustrated embodiment, the clamping assemblies comprise two vertical set screw assemblies  930   a - 930   b , and a lateral set screw assembly  940 . The vertical set screw assemblies  930   a - 930   b  each comprise one or more vertically-oriented set screws  950  which can be tightened so as to apply a downward force on the upper side of the receiver  1310 , thereby providing a more secure coupling between the flange members  912 ,  922  and the upper cover  1320 . 
     In some embodiments, it may be desirable to distribute the downward force applied by the set screws  950  onto the top of the receiver  1310  over a larger area than just the lower ends of the set screws  950 , so as to prevent the ends of the set screws  950  from digging into the top of the receiver  1310 , thereby marring the firearm  1300 . One or more force-distributing top plates  1110  (labelled in  FIG. 11B ) can be coupled to the lower ends of the set screws  950  so as to be positioned between the set screws  950  and the top surface of the receiver  1310  in order to distribute the load applied by the set screws  950  over a larger surface area. In some embodiments, these force-distributing top plates may be made of a material that is softer than the material of the receiver  1310 , e.g., brass plates used with a steel receiver. This can further serve to prevent or minimize marring of the receiver  1310 . The force-distributing top plates may be made of any suitable material and design. For example, in one embodiment, a round brass plate is coupled to the end of each set screw, e.g., by swaging the plate to the end of the corresponding set screw. In other embodiments, a force-distributing plate is coupled to a plurality of set screws, so as to provide a larger surface area over which the forces from the set screws as distributed. 
     Similarly, the lateral set screw assembly  940  may comprise one or more laterally-oriented set screws  950  which can be tightened so as to apply a lateral force on a lateral side of the receiver  1310 . In the illustrated embodiment, the lateral set screw assembly  940  is provided on the left side member  910  so that the set screws  950  apply a force on the left side of the receiver  1310 , thereby providing a more secure coupling between the right side member  920  and the right side of the receiver  1310 . One or more force-distributing side plates may also be used, as described above. 
     The set screws  950  may be configured to receive a hex key for tightening and loosening. In some use cases, the base assembly  110  will frequently be left coupled to the firearm  1300  for extended periods of time (e.g., several days or more), and the top mount  150  with an accessory still attached is removed much more frequently (e.g., every day) in order to separate the accessory from the firearm. The use in some embodiments of hex key set screws  950  may cause the user to spend a greater length of time for attaching and detaching the base assembly  110  from the firearm  1300  than embodiments utilizing clamps or other tool-free mechanisms. However, the burden imposed may be offset by the less frequent need to detach the base assembly  110  from the firearm  1300 . 
     In other embodiments, other types of clamping assemblies may be used to securely and releasably couple the base to the firearm. For example, different numbers, sizes, and configurations of set screw assemblies, set screws, and force-distributing plates may be used in place of the illustrated design. 
     Some conventional accessory rail systems are attached to the firearm using clamps. Because these clamps provide a fixed amount of travel between the unclamped and fully clamped positions, they may not effectively accommodate variations in the sizes of the various components. For example, in some cases, either the rail system or the receiver may become deformed over time, which can reduce the force applied by the clamps and possibly result in movement of the rail system during use. In other cases, different receivers may have slightly different widths, which can cause the clamps to apply either a greater or lesser clamping force than intended. In accordance with embodiments of the present invention, because the clamping assemblies utilize set screws  950  which can be tightened to a desired torque level, the clamping forces applied by the set screws  950  can be precisely controlled, despite variations in the dimensions of the base  110  and/or the receiver  1310 . 
     In the illustrated embodiment, the mount connector portion  114  of the base assembly  110  comprises a Picatinny rail, also known as a MIL-STD-1913 rail, which extends longitudinally along the top side of the base assembly  110 , parallel with the direction of aim of the firearm. The base connector portion  154  of the top mount  150  may utilize any of a variety of designs for coupling the top mount  150  to the mount connector portion  114 . In the illustrated embodiment, the base connector portion  154  comprises a fixed lower flange  510  and a side clamping mechanism  520 . The side clamping mechanism  520  comprises a pair of levers  522  and a movable side clamp flange  524 . When the levers  522  are closed, the side clamp flange  524  applies a lateral force onto the side of the rail (mount connector portion  114 ) to securely retain the rail between the side clamp flange  524  and the lower flange  510 . Advantageously, these levers  522  provide a secure coupling, but can also be quickly and easily released manually without the use of tools. 
     In the illustrated embodiment, a body portion  916  of the top mount, the lower flange  510 , and the accessory mounting rail connector  152  are formed by a single metal component, with the side clamp flange  524  coupled to the body portion  916  using screws  526  which extend from the lower flange  510  side of the top mount  150  to the side clamp flange  524 . In other embodiments, the design and components for attaching the side clamp flange can vary. 
     In some embodiments, the top mount  150  may include one or more additional accessory mounting rail connectors  152 . As shown in  FIG. 5A , the top mount  150  includes a modular accessory attachment region  540  on the side of the body portion  530  to which an additional accessory mounting rail connector (not shown) may be attached. This additional rail would be oriented such that the position of the rail is rotated 90° relative to the accessory mounting rail connector  152 . In the illustrated embodiment, the modular accessory attachment region  540  comprises a recess with two openings for coupling with fasteners on the additional accessory mounting rail connector. An additional accessory can then be mounted to the accessory mounting rail connector. In other embodiments, the modular accessory attachment region can be omitted entirely or multiple the modular accessory attachment regions can be provided, depending on the desired accessory compatibility. 
     Offset Mount Connector 
     Many firearms, such as crew-served machine guns, are mounted onto vehicles and equipped with gun shields for protecting the operator of the firearm. These gun shields typically comprise a metal plate with an opening through which the barrel group of the firearm extends. During operation, it is desirable to enable the operator to keep his or her head as low as possible in order to maximize the amount of coverage provided by the gun shield. However, when a conventional accessory mount is attached to the top of the firearm, the optics accessory attached to the accessory mount is positioned far above the top of the firearm, thereby requiring the operator to extend his or her head farther above the top of the firearm in order to use the optics. 
     In accordance with embodiments of the present invention, the accessory mounting system  100  utilizes a low-profile design so as to position the accessory closer to the firearm than conventional mounts. A low-profile design can be achieved using an offset lateral centerline of the mount connector portion  114 . The front plan view of  FIG. 4A  illustrates the locations of the lateral centerlines for various components of the system. The lateral centerline  440  of the base assembly  110  extends through the point approximately midway between the interior surfaces of the left side member  910  and the right side member  920 . When the base assembly  110  is mounted on the receiver  1310 , the centerline  440  of the base assembly  110  aligns with the lateral centerline  410  of the receiver  1310 . In addition, the centerline  430  of the accessory mounting rail connector  152  aligns with the centerline  440  of the base assembly  110 , and, therefore, also aligns with the lateral centerline  410  of the receiver  1310 . This may be desirable so that the optics or other accessory mounted to the accessory mounting rail connector  152  is also laterally aligned with the centerline  410  of the receiver  1310 . 
     In accordance with embodiments of the present invention, the lateral centerline  420  of the mount connector portion  114  of the base  110  is laterally offset from the centerline  430  of the accessory mounting rail connector  152  and the centerline  410  of the receiver  1310 . As a result of this offset, the levers  522  may be positioned closer to the side of the base assembly  110  and directly above the top of the base assembly  110 , thereby improving the operator&#39;s access to the levers  522 . In some embodiments, the bottom side of the levers  522  are positioned less than approximately 3 mm, 2 mm, or 1 mm above the upper surface of the base assembly  110 . If the levers  522  were positioned closer to the centerline  440  of the base  110 , the body portion  916  of the base  110  would get in the way, thereby making it more difficult for the operator to reach the levers  522  with his or her fingers. To overcome this, the levers  522  may be positioned further away from the top of the base assembly  110 , so as to provide easier access to the levers  522  without the body portion  916  getting in the way. However, this could cause an undesirable increase in the overall height of the system  100 . 
     In accordance with embodiments of the present invention, the accessory mounting system  100  provides a low profile such that the distance from the top of the accessory mounting rail connector  152  to the top of the receiver  1310  is less than approximately 2.5″, 2.1″, or 2.0″. 
     It is noted that the centerlines  410 ,  430 , and  440  may be considered to be aligned even though they are not in precisely the same location, due to the slack provided between the left side member  910  and the right side member  920  which is taken up by the lateral set screw assembly  940 , as well as other tolerances and deviations. In some embodiments, the centerlines  410 ,  440 , may be separated by any distance that avoids an undesirable level of lateral error in the zeroing procedures for the mounted optics and still be considered as being aligned. In one example, an acceptable level of offset of the centerlines is up to 5 mm. When used with an M2 firearm, a 5 mm offset of the centerlines would produce a 50 cm lateral error at 1000 m, which could be an acceptable level of variation. Accordingly, up to a 5 mm offset of the centerlines would still be considered as being aligned. In other embodiments, an offset of up to approximately 1 mm would be considered as being aligned. 
     Sight Access Features 
     Many firearms, such as the M2, are provided by default with an iron sight system. As described herein, embodiments of the present invention can provide users with the option of utilizing more modern and useful sighting systems in place of or to supplement these standard iron sights. Conventional iron sight systems can comprise two component sights: a rear sight mounted on the top of the receiver and a front sight provided on the top of the barrel or barrel group. Any structure that is attached to the top of the receiver  1310  of a firearm  1300  could potentially interfere with the operator&#39;s use of the iron sight system. 
     In accordance with embodiments of the present invention, a firearm accessory mounting system is provided which can be attached to the top of a receiver of a firearm while still enabling use of and/or access to the iron sight system. 
     In some embodiments, the top mount  150  includes a sight passage opening  155 , which extends the length of the top mount  150  such that a line of sight from the rear sight to the front sight passes through the sight passage opening  155 , thereby enabling an operator to utilize the iron sight system in addition to the use of an accessory attached to the top mount  150 . In some embodiments, the bottom  156  of the sight passage opening  155  is positioned approximately 23 mm above the top of the receiver  1310 , which leaves the 8.5 mm rear ring of the M2 iron sight substantially unobstructed. 
     In some embodiments, the top mount  150  may include a sight access cutout  200  (as can be seen in  FIGS. 1 and 2A-2B ). In many firearms, e.g., the iron sight system includes a knob or other adjustment mechanism that the operator must access from the lateral side of the firearm (not shown in  FIG. 13 ). In embodiments in which the rail connector  152  extends rearward on the firearm  1300  such that it overlays the iron sight adjustment mechanism, the sight access cutout  200  provides a thinner side profile for the top mount  150  than the portion of the top mount  150  coupled to the base  110 , as can be seen in  FIGS. 2A-2B . This cutout  200  is positioned so as to provide the operator with unobstructed access to the adjustment mechanism on the side of the iron sight system. In one example, the iron sight adjustment knob for an M2 firearm is 15.6 mm in diameter and is located approximately 60 mm from the rear of the receiver  1310  (not including the spade grip assembly) and approximately 17 mm from the top of the receiver  1310 . The cutout  200  positioned to provide unobstructed access to the adjustment knob. 
     While the invention has been described in terms of particular embodiments and illustrative figures, those of ordinary skill in the art will recognize that the invention is not limited to the embodiments or figures described. For example, in various embodiments described above, the firearm accessory mounting system is sized and configured for use with an M2 machine gun. Many of the aspects described herein are particularly desirable when used with belt-fed, crew-serviced M2 machine gun, which is a very heavy firearm with a large receiver system. For instance, example mounting systems described above can provide a low profile for an optics mount, while still having a pass-through to utilize the standard M2 iron sights. In addition, the ability to quickly detach the top mount from the base, and then re-index the accessory to the same location upon re-mounting can improve the ease and speed with which soldiers can comply with accountability requirements for sensitive items, such as optics and other accessories. In other embodiments, the system may be sized and configured for use with other types of weapons, including, e.g., other types of belt-fed and/or crew-serviced firearms. 
     The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the invention. In this regard, no attempt is made to show details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings and/or examples making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural and singular number, respectively. Additionally, the words “herein,” “above,” and “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of the application. 
     The description of embodiments of the disclosure is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. While specific embodiments and examples for the disclosure are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize. Such modifications may include, but are not limited to, changes in the dimensions and/or the materials shown in the disclosed embodiments. 
     Specific elements of any embodiments can be combined or substituted for elements in other embodiments. Furthermore, while advantages associated with certain embodiments of the disclosure have been described in the context of these embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the disclosure. 
     Therefore, it should be understood that the invention can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be understood that the invention can be practiced with modification and alteration and that the invention be limited only by the claims and the equivalents thereof.