The present invention relates generally to accessory mounting assemblies for combat weapons such as the modular integrated accessory systems found on most modern combat weapons. More specifically, the present invention relates to a mounting assembly including a shoulder formation that prevents over rotation of the actuator arm when moved to the open position.
As the field of combat and commercial weaponry expands, numerous add-on enhancements have become available for attachment to standard firearms, thereby significantly upgrading the capability of the firearm. Of particular interest in the area of combat weapons is the well-known M16/M4 weapon system (M16 and M4 are trademarks of Colt Defense, Inc.). The M16 has been in service for a number of years and will continue to be a popular rifle both in U.S. and foreign militaries for the foreseeable future. Generally, the M16/M4 weapon 2, as depicted in FIG. 1, includes a lower receiver 4, upper receiver 6, butt stock 8, and barrel 10.
The newer models of the M16/M4 weapons further include a mil-std 1913 dovetail rail 12 extending along the top of the upper receiver. This integrated receiver rail 12 provides a convenient mounting point for many types of enhancement devices such as scopes and other sighting devices. However, space on the upper receiver rail 12 is limited, and many military personnel often have multiple sighting devices that are each tailored to perform in different combat situations. In addition, there are a variety of lighting devices, handgrips, etc. that could also be attached to the weapon for enhanced use of the weapon. The difficulty is that there is simply not enough space on the integrated rail provided on the upper receiver to accommodate all of the desired accessories. Accordingly, the increasing development and refinement of laser sights, infrared lighting, visible lighting, night vision, and specialized scopes and magnifiers, and other accessories continues to drive the need for versatile and reliable integration systems that include additional mil-std 1913 dovetail rails positioned above or around the barrel of the weapon that can support this important equipment and yet stand the test of rugged military use and abuse.
Responding to this need, the applicant has developed a modular integrated rail system (A.R.M.S.® S.I.R.® system), which has been well received by the military and has become popular with several branches of the military (See FIG. 2). The A.R.M.S. S.I.R. system is fully described in U.S. Pat. No. 6,490,822, the entire contents of which are incorporated herein by reference. These modular integrated rail systems for combat weapons 2 generally include an upper hand guard 14, a means 16 for securing the upper hand guard 14 to the weapon 2, a lower firearm accessory 18 (in most cases this is a lower hand guard), various optional rail segments, and in many cases, a sling swivel 20 for attaching a shoulder sling to carry the weapon 2.
The upper hand guard 14 is the main structural element of the system. The upper hand guard is 14 generally semi-cylindrical in shape and has a forward end and a rearward end and a mil-std 1913 dovetail rail 22 extending longitudinally between the forward end and the rearward end. The semi-cylindrical upper hand guard 14 further includes symmetrically opposing side walls that extend outwardly and downwardly from the dovetail rail and terminate in symmetrically opposing longitudinally extending mounting channels. The mounting channels are used to mount various accessories, such as a lower hand guard 18 or a grenade launcher, to the upper hand guard 14.
An interface means 16 is provided at the rearward end of the upper hand guard 14 to removably secure the upper hand guard 14 to the firearm 2. In the original S.I.R. system as shown in U.S. Pat. No. 6,490,822, the clamp is an elongated clamping rail that secures the upper hand guard 14 to the dovetail rail 12 on the top of the upper receiver 6 of the weapon 2. In the newer S.I.R. systems, the interface means is a U-shaped yoke or clamp that secures the upper hand guard 14 to the barrel nut.
As is well known in this area, field modification of weapons is critical in combat situations. For example, it may be desired to swap the lower hand guard for a grenade launcher, which can be attached to the upper hand guard, or to add an optional rail segment for securing an added accessory. Similarly, there may be a desire to exchange various different sights or lighting accessories that are mounted on the various dovetail rails positioned around the weapon. In this regard standardized attachment assemblies have been developed to allow quick and easy removal and mounting of these devices relative to the dovetail rails. Such an attachment device was disclosed in U.S. Pat. No. 5,276,988, issued on Jan. 11, 1994 to the present applicant, the contents of the patent being incorporated herein by reference. Generally, the prior art attachment assemblies included a main body having a lower portion that is configured to engage the dovetail rail found on most modern combat weapons and an upper portion that can take on a variety of configurations depending on the accessory that is to be mounted thereon. The lower portion of the mounting assembly has a first engagement member extending downwardly along one side thereof for engaging one side of the dovetail rail. Further, a boss formation is provided adjacent the side of the main body to receive a clamping assembly that is particularly suited to be releasably engageble with a second side of the dovetail rail such that the clamping assembly cooperates with the first engagement member to retain the modular mounting assembly in its installed position on the dovetail rail.
The difficulty with the prior art attachment assemblies is that the actuator arm that serves to open and close the clamping portion of the attachment assembly is typically allowed to freely rotate over a full 180-degree arc. In this configuration, while a positive closed/locked position is provided a positive open position is not provided. As the clamping foot of the mounting assembly is released, it can tend to be over rotated to a point where it begins to reengage the firearm rail system. As a result, such over rotation can interfere with easy installation and removal of the mounting assembly. Further, in the typical military environment, as the devices become dirty, there exists a need to have positive and repeatable positioning of the various components since fussy devices having small tolerances often interfere with the device operation in such rugged operating environments.
Accordingly, there is a perceived need for an improved modular mounting assembly that allows for the releasable mounting of various accessories onto the standard dovetail rail found on modern combat weapons. Further, there is a perceived need for a modular mounting assembly that can be reliably mounted onto a dovetail rail while including an actuator that includes an indexing means to indicate that the actuator is in the correct locked or open position.