Patent Publication Number: US-7584567-B1

Title: Hand guard assembly for firearms

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional application of currently U.S. application Ser. No. 11/174,270, filed 29 Jun. 2005, now U.S. Pat. No. 7,363,741 which claims the benefit of U.S. Provisional Application No. 60/585,746, filed 6 Jul. 2004. 

   FIELD OF THE INVENTION 
   This invention relates to accessories for firearms. 
   More particularly, the present invention relates to hand guards that may include one or more accessory rails. 
   BACKGROUND OF THE INVENTION 
   It is understood that hand-held firearms require some type of handgrip so that the operator can hold the firearm as it is fired. Also, many accessories are available that aid in the proper and/or enhanced operation of firearms and some type of platform or mounting structure is generally provided or available as an accessory for this function. Further, many firearms are operated as automatic or semiautomatic and have a tendency to heat extensively so that handgrips attached directly to the barrel can produce hand burns for the operator if great care is not taken. In addition, anything attached directly to the barrel of a firearm can have a tendency to alter the barrel slightly and any alterations can adversely affect the accuracy of the firearm. 
   As understood by those skilled in the art, firearms of the type discussed herein generally include a receiver a stock attached to one end of the receiver and a barrel attached to the other end of the receiver. In most instances the barrel screws into an opening in the receiver and includes a barrel nut adjacent the receiver for assembling the barrel into the receiver. In most instances, handgrips or hand guards and accessory mounting devices are attached to the barrel. Further, the operator must grip the firearm on or adjacent the barrel to stabilize the firearm during operation. Thus, hand guards generally surround at least portions of the barrel to provide the operator a place to grip the firearm and to protect the hand from the heat of the barrel. 
   One of the main problems that arises is the weight that hand guards and accessory mounting devices add to the firearm. Clearly, the hand guards and accessory mounting devices must be constructed ruggedly and to withstand heavy use. In the prior art, hand guards are constructed of a plurality of components that are fixed together around the barrel, generally by screws or the like. Because the prior art hand guards are formed with multiple components, they must be constructed with larger and heavier areas or portions (e.g. mating edges, etc.) that are adapted to allow the components to be fixed together. 
   It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art. 
   Accordingly, it is an object of the present invention to provide a new and improved hand guard assembly. 
   Another object of the invention is to provide a new and improved hand guard assembly that is relatively light weight. 
   Another object of the invention is to provide a new and improved hand guard assembly and that may include one or more accessory mounting devices. 
   Another object of the invention is to provide a new and improved hand guard assembly that is simpler to manufacture and to install. 
   Another object of the invention is to provide a new and improved hand guard assembly that is relatively cool and that enhances air flow over the underlying barrel. 
   SUMMARY OF THE INVENTION 
   Briefly, to achieve the desired objects of the instant invention in accordance with a preferred embodiment thereof, provided is a hand guard assembly for a firearm including a barrel. The assembly includes a tubular unitary body mounted to surround a portion of the barrel substantially coaxially and in a transversely spaced relationship. The tubular body includes a plurality of air flow openings formed therethrough. The hand guard assembly may also include any one of a top rail formed as a unitary portion of the tubular body and extending rearwardly along an upper portion of a receiver of the firearm, side accessory rails formed as a unitary portion of the tubular body and on opposed sides of the tubular body, and a bottom accessory rail formed as a unitary portion of the tubular body and on a bottom surface of the tubular body. 
   In a preferred method of fabricating the assembly, the body and any included accessory rails are extruded as a unitary structure. Also, portions of material are removed from the accessory rails to define the air flow openings as well as opposed longitudinally extending side grooves, the side grooves defining external reference surfaces for mounting accessories, a longitudinally extending central groove formed midway between the opposed side grooves and defining internal reference surfaces for mounting accessories, a plurality of transverse ribs with adjacent ribs being separated by crosscuts, and a plurality of pocket cuts formed intermediate the transverse ribs and along the central groove. The removal of the material also substantially reduces the weight and thermal mass. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Specific objects and advantages of the invention will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment thereof, taken in conjunction with the drawings in which: 
       FIG. 1  is a perspective view of a portion of a firearm illustrating a hand guard assembly according to the present invention; 
       FIG. 2  is a top plan view of the hand guard assembly of  FIG. 1 ; 
       FIG. 3  is a side plan view of the hand guard assembly of  FIG. 2 ; 
       FIG. 4  is a sectional side view of the hand guard assembly, taken along line  4 - 4  of  FIG. 2 ; 
       FIG. 5  is a sectional view of the hand guard assembly of  FIG. 2 , taken along line  5 - 5 ; 
       FIG. 6  is a sectional view of the hand guard assembly of  FIG. 2 , taken along line  6 - 6 ; 
       FIG. 7  is an enlarged partial view of the hand guard assembly of  FIG. 2 ; 
       FIG. 8  is a sectional view of a portion of a rail of  FIG. 7 ; 
       FIG. 9  is a top plan view illustrating the hand guard assembly including an accessory rail system, according to the present invention, with a rail cover and an accessory mounted on a side rail; 
       FIG. 10  is an enlarged partial top view of the hand guard assembly with portions of the rail cover cutaway; 
       FIG. 11  is an enlarged partial side view of the hand guard assembly with portions of the rail cover cutaway; 
       FIG. 12  is a sectional view of the hand guard assembly illustrated in  FIG. 9  with a rail cover mounted on a side accessory rail; and 
       FIG. 13  is a sectional view of the hand guard assembly illustrated in  FIG. 9  with an accessory carried by a side accessory rail. 
   

   DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
   Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, attention is directed to  FIG. 1  which illustrates a portion of a firearm having a barrel  10  extending from an upper receiver  12 . A hand guard  14 , including side accessory rails  15 , bottom accessory rail  16  and top rail  18 , is carried by the portion of the firearm illustrated. Hand guard  14  is preferably extruded as a single piece having each element integrally formed therewith. This unitary construction adds strength while allowing removal of material, as will be described presently, to reduce weight and thermal mass. While hand guard  14  is illustrated mounted on a rifle, it will be understood that it may be mounted on substantially any firearm. Additionally, while side accessory rails  15 , bottom accessory rail  16  and top rail  18  are illustrated carried by hand guard  14 , some or all may be omitted as desired or included in conjunction with other firearms and/or other hand guard systems, as will be explained in more detail below. Hand guard  14  and/or any or all of side accessory rails  15 , bottom accessory rail  16  and top rail  18  are referred to herein generally as a “hand guard assembly”. Additionally, the unique structure of the accessory rails, as will be described presently, can be employed on any firearm, including artillery pieces, without the use of a hand guard or in conjunction with other hand guard systems. The accessory rails adhere to all the critical dimensions of the Mil-1913 standard Picatinny rail. 
   Referring now to  FIG. 2 , the following description of hand guard  14  includes a description of the various accessory rails. Those skilled in the art will understand that hand guard  14  may be employed without accessory rails, and conversely, the accessory rails can be employed on other hand guard systems or firearms in general. Hand guard  14  includes a tubular body  20  which is received about barrel  10  of the firearm. Tubular body  20  is preferably fabricated of metal, such as aluminum, by extrusion. In this preferred embodiment, side accessory rails  15 , bottom accessory rail  16 , and top rail  18  are extruded with body  20  in a unitary piece. Top rail  18  is preferably formed with tubular body  20  and is typically employed to engage the top rail of upper receiver  12 . Hand guard  14  can, for example, engage the barrel nut of barrel  10  for support, with additional support being provided by top rail  18 , if present. In this fashion hand guard  14  is supported in spaced relationship to barrel  10  to allow air flow therebetween. 
   In the event that one or all of side accessory rails  15 , bottom accessory rail  16 , and top rail  18  are used without tubular body  20 , they may be attached to a firearm by means of another hand guard system or by structure other than a hand guard, e.g. attachment rings, rails, or other mounting devices. In this disclosure, structure mounting one or all of side accessory rails  15 , bottom accessory rail  16 , and top rail  18  is included in the term “mounting structure”, which is intended to include any structure mounting one or all of side accessory rails  15 , bottom accessory rail  16 , and top rail  18  on a firearm, including tubular body  20 . Further, one or all of side accessory rails  15 , bottom accessory rail  16 , and top rail  18  and the mounting structure for the rail or rails in included in the term “hand guard assembly” as used in this disclosure. 
   Hand guard  14  is a unitary structure including accessory rails, and material removed to greatly reduce weight without affecting strength. In this disclosure the term “unitary” denotes a construction in which all of the components are formed integrally or as a single piece. Longitudinal slots/openings  22  are formed in body  20  intermediate side accessory rails  15  and bottom accessory rail  16  to reduce weight and promote airflow between body  20  and barrel  10 . Due to the unitary nature of hand guard  14  with associated rails, removal of material does not substantially weaken the overall structure. 
   With continued reference to  FIG. 2 , and additional reference to  FIGS. 3-8 , the weight of hand guard  14  is further reduced by removing material from the accessory rails. Side accessory rails  15  and bottom accessory rail  16  are substantially identical, therefore only one will be described in detail. Side accessory rails  15  include inner external referencing surfaces  31  and  32  (best seen in  FIG. 8 ), defined by opposing longitudinal side grooves  33  and  34 , respectfully. Outer external referencing surfaces  31   a  and  32   a  adjoin inner external referencing surfaces  31  and  32 . Internal referencing surfaces  37  and  38  are defined by a central longitudinal groove  39 . A plurality of equally spaced transverse ribs  40  (best seen in  FIG. 7 ) are formed the length of accessory rail  15  by a plurality of crosscuts  42 . Transverse ribs  40  include vertical thrust surfaces  43  which prevent forward and rearward movement of accessories attached thereto. Pocket cuts  45  are formed intermediate transverse ribs  40  along central groove  39 . The inclusion of pocket cuts  45  greatly reduces the weight and thermal mass of hand guard  14 . Pocket cuts  45  can be formed completely through the material in the form of through holes, to provide higher levels of air flow. This is not preferred on the top rail, as heated air can cause distortions in the sight path. To complete the shape of accessory rails  15 , undercuts  48  are formed between each rib  40  from each longitudinal side groove to the crosscuts  42 . Undercuts  48  join longitudinal side grooves  33  and  34  with crosscuts  42  and pocket cuts  45  to form an air path transversely through each accessory rail. 
   The air path is illustrated with reference to  FIGS. 9-12 . As can be seen, when a rail cover  50  is placed on side accessory rail  15 , undercuts  48  provide air access under cover  50 . In this manner, circulating air continues to cool hand guard  14  even with rail covers  50  in place. 
   Turning now to  FIG. 12 , rail cover  50  is illustrated coupled to side accessory rail  15 . It will be understood that rail covers  50  can also be affixed to bottom accessory rail  16 . With reference to  FIG. 13 , an example of an accessory, sling mount  52 , is illustrated carried by side accessory rail  15 . Many accessories clamp over the rail and are indexed by external referencing surfaces  31 ,  32  and/or  31   a ,  32   a  (see for example rail cover  50  in  FIG. 12 ). In this example, sling mount  52  is indexed by internal referencing surfaces  37 ,  38 . Thus, various accessories can be employed using either external indexing surfaces or internal indexing surfaces. Additionally, it should be understood that top rail  18  is substantially similar to accessory rails  15  and  16 , with the omission of central groove  39 . It should also be understood that the central groove  39  can be employed if desired. 
   Various changes and modifications to the embodiments herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof which is assessed only by a fair interpretation of the following claims.