Abstract:
An accessory to improve handling and transportability of a belt-fed firearm attaches to an upper surface of the firearm and provides at least two protrusions extending outward or upward therefrom, the protrusions sized and positioned to engage a portion of the ammunition belt between two rounds of ammunition and to prevent the belt from sliding across the upper surface of the firearm.

Description:
CONTINUITY AND CLAIM OF PRIORITY 
       [0001]    This is an original U.S. patent application. 
       FIELD 
       [0002]    The invention relates to firearm accessories. More specifically, the invention relates to structural features of a machine gun to improve its handling characteristics when it is not in use. 
       BACKGROUND 
       [0003]    A wide variety of firearms have been developed and used in sport, hunting and combat. One of the most intimidating and effective weapons is the fully-automatic machine gun, which allows its operator to fire continuously at rates of 500, 1,000, or even more rounds per minute. Machine guns were originally large, heavy and temperamental devices, but with the benefit of modern materials and manufacturing techniques, a highly-capable machine gun can be small and light enough to be carried by a single soldier. 
         [0004]    Ammunition for a machine gun is often provided as a linked belt or chain of cartridges, each round of which may be identical to the non-linked version used in other types of firearm. The action of the machine gun draws the belt through a feed mechanism to bring live rounds into the firing chamber, and then to expel discharged cases. The action is more complex than that of a non-machine firearm (e.g., a clip-fed semi-automatic pistol), and may be more time-consuming to load and prepare for operation. Consequently, machine guns are often prepared and pre-loaded with a short “starter belt” of ammunition, which can easily be attached to the end of a longer chain of ammunition when the weapon is to be used. (Of course, the rounds of the starter belt are also live, and so the weapon can be fired if necessary even before the main belt is attached.) 
         [0005]    The starter belt typically hangs clown from the weapon&#39;s feed mechanism, and a length containing a useful number of rounds may be 2-3 feet (60-90 cm) long. This heavy, flexible belt can interfere with the motion of a soldier carrying the weapon, and if the end of the belt drags through mud or sand, it can carry those contaminants into the firing mechanism and cause jams or misfires. Some soldiers attempt to prevent this by folding the belt over the barrel of the weapon, but between the weight of the cartridges and the smooth, flexible design of the belt, it is difficult to keep the starter belt from falling or sliding all the way to one side or the other. 
         [0006]    A mechanism for securing the starter belt of a belt-fed weapon against such undesired movement may improve the handling and portability of the firearm, and thereby improve the operator&#39;s mobility, effectiveness and safety. 
       SUMMARY 
       [0007]    An ammunition restraining device attached to the barrel or other upper surface of a belt-fed firearm, or otherwise formed on the upper surface of the weapon, helps hold a belt of ammunition in place while the weapon is being carried or moved. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]    Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
           [0009]      FIGS. 1A-1D  show several views of a prototype ammunition restraining device according to an embodiment of the invention. 
           [0010]      FIG. 2  shows a belt-fed machine gun being carried by a soldier. A short length of linked ammunition is draped across the top of the weapon, where it is secured by an embodiment of the invention. 
           [0011]      FIG. 3  shows a detail of a portion of an ammunition belt and two protrusions of an embodiment which fit between adjacent shells. 
           [0012]      FIG. 4  shows another representative view of a belt-fed firearm with an embodiment of the invention attached to its upper surface. 
           [0013]      FIGS. 5A and 5B  show an alternate embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Embodiments of the invention are attached to or formed on an upper surface of a machine gun to prevent a length of linked ammunition draped over the weapon from sliding from side to side while the weapon is being moved. A simple mechanical structure avoids introducing unnecessary complexity that might harm the weapon&#39;s reliability. 
         [0015]      FIGS. 1A-1D  show several views of a prototype ammunition restraining device (generally identified by reference number  100 ) according to an embodiment of the invention. In side view  1 A, a clamping mechanism is visible at  110 . This mechanism is used to attach the device to an upper surface of a firearm by clamping it to an accessory rail, scope mount, or other suitable feature of the firearm. This embodiment only has a single attachment point; the other end of the device  120  simply rests on top of the weapon. The device has two protrusions or “fingers,”  130  and  140 , which extend upward from the top of the device (and from the top of the weapon). 
         [0016]    Top view  1 B shows a threaded bolt  150  which is used to tighten the clamping mechanism. Protrusions  130  and  140  are visible in this view also. The distance  160  between the protrusions is chosen to suit the ammunition and link or belt system used by the firearm, as described below. Front view  1 C shows the moveable portion  170  of the clamping mechanism, one of the protrusions on the top ( 130 ) and the rear resting pad  120 . 
         [0017]      FIG. 1D  is a perspective view of the prototype ammunition restraining device. 
         [0018]    Although the prototype device shown in  FIGS. 1A-1D  uses a screw-driven clamping mechanism to secure it to a firearm, those of ordinary skill will appreciate that other attachment methods are also acceptable. For example, a lever-actuated, cam-based clamp may be attractive because it can be adjusted without tools. Multiple clamping mechanisms may provide improved resistance to loosening and inadvertent detachment, at a cost of increased manufacturing complexity and expense. Other embodiments may be secured more-or-less permanently to a firearm by means of latches, expanding pins, threaded fasteners, rivets or the like. For new firearm designs, the improved functionality offered by an embodiment of the invention can be obtained by designing protrusions as described below directly into the weapon barrel, stock, or a similar location. 
         [0019]      FIG. 2  shows a soldier  200  carrying a typical belt- or linked-ammunition-fed machine gun  210 . A short length of ammunition (a “starter belt”) is shown draped across the top of the weapon. An embodiment of the invention, secured to the barrel under the starter belt, helps prevent the belt from sliding off the weapon and interfering with the soldier&#39;s movement, becoming tangled in underbrush or fouled with water, mud or sand. Since the embodiment can prevent side-to-side movement of the belt when engaged between any two rounds of ammunition, the belt overhang on either side can be easily adjusted regardless of the length of the starter belt. For longer starter belts, a second embodiment may be attached further forward on the weapon to secure a second side-to-side fold of the belt. 
         [0020]    In this condition, the weapon may still be immediately operable, and since the starter belt is merely held in place against the protrusions by its own weight, it can be unfolded quickly and reliably, with no risk of jamming or other failure that might be caused by an attachment clip of greater mechanical complexity. 
         [0021]      FIG. 3  shows a portion of an ammunition belt, seen from above as it would cross the top surface of a firearm when draped as shown in  FIG. 2 . In this view, the tops of two protrusions of an embodiment are visible at  330  and  340 . The horizontal distance between the protrusions (i.e., the distance along the main axis of the firearm, viz.  160  in  FIG. 1B ) is less than the length of a round of ammunition  300 , but greater than the width of the link or belt material  310 . It is preferred that the protrusion spacing be comfortably larger than the belt width, so that the belt need not be draped across the weapon particularly carefully. 
         [0022]      FIG. 4  shows a rear view of an ammunition belt  400  draped over the body of a firearm  410 . At  420 , the profile of an embodiment of the invention is shown. The rear protrusion is visible, and can be seen to be slightly shorter than the diameter of a cartridge. A longer (i.e., taller) protrusion might provide an improved securing function, but could also interfere with normal operation of the weapon, while a shorter protrusion might be less effective at preventing sliding. It is preferred that the protrusions extend by a length between ½ and 1½ times the diameter of the cartridge. 
         [0023]      FIG. 5A  shows an alternate embodiment that may be easier to manufacture, but may be less rugged than the metal or composite, clamp-on version discussed above. A flexible, ridged pad  510  may be made of a polymer or similar material, and attached to the top portion of a weapon by adhesive, screws, or similar means. The plurality of protrusions or ridges are spaced and formed to correspond to the shells in a belt of ammunition, so a belt draped across the pad is held in place somewhat like a chain on a sprocket. This is shown in  FIG. 5B , where ammunition belt  520  is draped over a firearm body, seen in profile at  530 . The ridged pad is shown end on, shaded, at  540 . Fore-and-aft movement can also be restricted by flanges at the front and back of the pad, or by protrusions similar to those of other embodiments described herein. As with other embodiments, ridges like those shown here can be formed directly in the material of the stock, rather than added on afterward. 
         [0024]    The applications of the present invention have been described largely by reference to specific examples and in terms of particular allocations of functionality to certain features. However, those of skill in the art will recognize that improved firearm handling characteristics can also be obtained by weapon features different from those specifically illustrated and described above, but that nevertheless fall within the scope of the scope of the following claims. Such features are understood to be captured by the claims, notwithstanding their lack of resemblance to the embodiments depicted in the Figures.