Abstract:
A stock interface can be slipped onto and attached to a standard CAR buffer tube. The stock interface provides structures for attaching a butt stock and stock interface attachments such as an ergonomic attachment, a container attachment, and a power attachment. Small arms ergonomics can be improved by providing a better cheek weld via an ergonomic attachment. Container attachments provide storage. Power attachments provide electrical power for items such as electronic sighting systems, lasers, lights, or any of the other electronic devices attached to a small arm.

Description:
RELATED APPLICATIONS 
       [0001]    This patent application claims the priority and benefit of U.S. Provisional Patent Application No. 60/833,712 filed on Jul. 27, 2006 entitled “Stock Interface” and which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments relate to fields of small arms, rifle stocks, and modular rifle stocks. Embodiments also relate to the fields of power sources and electrical interconnections. 
       BACKGROUND 
       [0003]    Small arms design has moved past using fixed stock elements to using adjustable or modular components. Adjustable or modular components are used to configure a firearm for specific uses or missions. For example, U.S. Pat. No. 3,348,328 issued to Roy discloses an adjustable stock for use in conjunction with a CAR buffer tube. A buffer tube is a tube mounted to the back of a firearm receiver. In most applications, when the firearm is discharged, the bolt travels back and into the buffer tube while a spring, called the buffer spring, supplies a force for decelerating the bolt and returning it to a forward position. FIG. 1B of U.S. Pat. No. 5,941,005 illustrates a spring in a buffer tube. 
         [0004]    Roy, however, uses a specially formed CAR buffer tube for use with his adjustable stock. Many buffer tubes are simply cylinders that are appropriately sized for holding a buffer spring and decelerating the bolt. The CAR buffer tube is a buffer tube with an elongated rib and a groove. The CAR buffer tube is a standard part of certain military issue small arms. U.S. Pat. No. 3,348,328 contains illustrations of a CAR buffer tube, a stock element that slides onto the CAR buffer tube, and a locking mechanism that can lock the sliding stock in a variety of positions. 
         [0005]    Standard CAR buffer tubes, such as those used with the M4 and M16 carbines, have been attached to shotgun receivers. Some shotguns equipped with CAR buffer tubes do not use a buffer spring within the CAR buffer tube to achieve semiautomatic operation. 
         [0006]      FIG. 11 , labeled as “prior art”, illustrates a side view of an idealized CAR buffer tube. A cylindrical tube  1101  has a threaded end  1102  for attachment to a receiver and an elongated rib  1103  extending radially. 
         [0007]      FIG. 12 , labeled as “prior art”, illustrates a bottom view of an idealized CAR buffer tube. The groove  1201  in the elongated rib  1103  can be seen. Holes  1202  are positioned in the undercut groove  1201 . An adjustable stock can be locked into position by a pin pressing into a hole  1202 . 
         [0008]      FIG. 13 , labeled as “prior art”, illustrates a cut view of an idealized CAR buffer tube. The cylindrical tube  1101  has a sidewall  1302  and an opening  1301  that can contain a buffer spring. The groove  1201  in the elongated rib  1103  can be seen. 
         [0009]    Other inventors have refined Roy&#39;s adjustable length butt stock. For example, U.S. Pat. No. 6,874,267, U.S. Pat. No. 6,651,371, disclose modular gunstock systems. Like Roy, these two inventions use a specially designed replacement buffer tube. An armorer trained to work on small arms replaces the original buffer tube with the replacement buffer tube. Users who are less specialized than the armorer can then configure the remainder of the modular gunstock system. Another example is U.S. Pat. No. 6,925,744 that refines Roy&#39;s adjustable length butt stock by adding compartment modules to the moveable butt stock element. 
         [0010]      FIG. 14 , labeled as “prior art”, illustrates a stylized toy replica  1401  firing a pellet  1402 . Many toy replicas, such as Airsoft toys, are pellet firing small arms replicas. Hobbyists enjoy engaging in mock non-lethal battles using toy replicas because they are realistic looking and fire non lethal, although often painful, pellets. Realistic toys are also used in small arms training because the toys can have the same weight, size, and accessories as firearms used in combat or police work. The toy replicas are often realistic enough that many after market accessories can be used with both small arms and with toy replicas. A toy replica of an AR16 or M4 carbine, however, uses an imitation CAR buffer tube  1403  and not a real CAR buffer tube. As such, a small arms accessory requiring replacement of the buffer tube is not suitable for use with a toy replica. The illustration of  FIG. 14  is stylized because, from a distance, a toy replica can be indistinguishable from an actual small arm. Those practiced in combat training and police training are familiar with toy replicas. 
         [0011]      FIG. 17 , labeled as “prior art”, illustrates a firearm  1701 . More specifically, the firearm is an M16 rifle or its&#39; civilian counterpart the AR15. The M16  1701  buffer tube is a cylindrical buffer tube inside the stock  1702 . The buffer tube is threaded to the lower receiver  1703  on one end and has a threaded hole in the other end. A bolt threaded into the threaded hole bolts the stock  1702  to the buffer tube. 
         [0012]      FIG. 18 , labeled as “prior art”, illustrates a firearm  1801  with an exposed buffer tube  1802 . The firearm is an M16 rifle as in  FIG. 17 . The butt stock is removed so that the buffer tube  1802  can be seen. A bolt  1803  such as that for bolting on the stock, is threaded into the threaded hole at the end of the buffer tube  1802 . 
         [0013]    Prior art systems, however, require trained armorers or lack a comfortable cheek weld for a marksman. As such, systems and methods are needed to address shortcomings in the prior art. 
       BRIEF SUMMARY 
       [0014]    The following summary is provided to facilitate an understanding of some of the innovative features unique to the embodiments and is not intended to be a full description. A full appreciation of the various aspects of the embodiments can be gained by taking the entire specification, claims, drawings, and abstract as a whole. 
         [0015]    Systems and methods providing an easily installable and configurable modular gunstock are needed. 
         [0016]    It is therefore an aspect of the embodiments to provide a stock interface and at least one fastener. The stock interface is specifically designed to slide over a CAR buffer tube. A fastener can exploit the undercut groove to fasten the stock attachment to the CAR buffer tube. For example, a properly sized nut can be positioned in the CAR buffer tube&#39;s groove so that a bolt can be inserted through the stock interface and threaded into the nut. Tightening the bolt fastens the stock interface to the CAR buffer tube in a fixed position. The stock interface can be provisioned for mounting stock interface attachments such as ergonomic attachments, container attachments, and power attachments. 
         [0017]    Stock interface attachments can be attached to a stock interface using dovetails, interlocking fingers, or threaded hard points. Captured dovetails and interlocking fingers allow the parts to be slid together or otherwise snapped into place. As such, most infantrymen have the requisite skill to configure or customize a firearm. A threaded hard point can also be used where a threaded part is inserted into the threaded hard point to fasten the stock interface attachment to the stock interface. 
         [0018]    An ergonomic attachment is designed to improve a marksman&#39;s or an infantryman&#39;s ability to use a firearm. Standard issue AR16 or M4 carbines have an adjustable stock on a CAR buffer tube. Accurate long distance shooting requires a comfortable and consistent cheek weld between the shooters face and the firearm. The CAR buffer tube, however, is positioned for producing a cheek weld but does not provide a comfortable or consistent cheek weld. A good cheek weld can be obtained by attaching a stock interface to the CAR buffer tube. A better one can be obtained by attaching an ergonomic attachment to the stock interface. 
         [0019]    A container attachment is a stock interface attachment containing a compartment that can hold items such as batteries, coins, rocks, or whatever else an infantryman can fit into the compartment. A container attachment can have multiple containers. Small container attachment can be attached side by side to the stock interface to provide multiple compartments. 
         [0020]    A power attachment is a stock interface attachment that provides electrical power through an electrical interconnect. The power source can be replaceable or a permanent part of the power attachment. For example, a power attachment can have a battery compartment for disposable batteries. Alternatively, a power attachment can permanently contain a fuel cell and, perhaps, a refillable fuel tank. 
         [0021]    An electrical interconnect provides a way to get electrical energy into or out of a stock interface attachment. Electrodes that produce an electrical contact when attached to the stock interface can be used. A plug and socket type electrical interconnect can be used such that power is supplied when the plug is connected to the socket. An inductive interconnect can be used where inductive coupling is used to transmit power while keeping the electrical components sealed away from harm. 
         [0022]    A stock can be attached to a mounting rail on the underside of the stock interface. For example, a Picatinny (M-1913) type mounting rail can be used. Picatinny rails and mounting hardware are well known to those practiced in small arms. As such, a stock with a Picatinny mounting configuration can be reliably and repeatedly attached to a Picatinny type mounting rail. Other types of rail can be equivalently used although the Picatinny is prevalent in many applications and markets. 
         [0023]    The mounting rail on the underside of the stock interface can have a regularly spaced holes such that a stock can be slid onto the mounting rail and locked into position by a pin that passes through a hole in the stock. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  illustrates a stock interface and stock interface attachments in accordance with aspects of the embodiments; 
           [0025]      FIG. 2  illustrates a stock interface in accordance with aspects of the embodiments; 
           [0026]      FIG. 3  illustrates a stock interface and container attachments in accordance with aspects of the embodiments; 
           [0027]      FIG. 4  illustrates a stock interface and ergonomic attachments in accordance with aspects of the embodiments; 
           [0028]      FIG. 5  illustrates a stock attached to the stock interface in accordance with aspects of the embodiments; 
           [0029]      FIG. 6  illustrates two container attachments that can be mounted side by side in accordance with aspects of the embodiments; 
           [0030]      FIG. 7  illustrates a power attachment with a electrical power compartment in accordance with aspects of the embodiments; 
           [0031]      FIG. 8  illustrates a power attachment with a fuel cell in accordance with aspects of the embodiments; 
           [0032]      FIG. 9  illustrates a power attachment with permanent batteries in accordance with aspects of the embodiments; 
           [0033]      FIG. 10  illustrates a cut view of a stock interface fixedly attached to a CAR buffer tube in accordance with aspects of the embodiments; 
           [0034]      FIG. 11 , labeled as “prior art”, illustrates a side view of an idealized CAR buffer tube; 
           [0035]      FIG. 12 , labeled as “prior art”, illustrates a bottom view of an idealized CAR buffer tube; 
           [0036]      FIG. 13 , labeled as “prior art”, illustrates a cut view of an idealized CAR buffer tube; 
           [0037]      FIG. 14 , labeled as “prior art”, illustrates a stylized toy replica firing a pellet; 
           [0038]      FIG. 15  illustrates clamping a stock interface to a CAR buffer tube in accordance with aspects of the embodiments; and 
           [0039]      FIG. 16  illustrates clamping a stock interface to a buffer tube in accordance with aspects of the embodiments; and 
           [0040]      FIG. 17 , labeled as “prior art”, illustrates a firearm  1701 ; and 
           [0041]      FIG. 18 , labeled as “prior art”, illustrates a firearm  1801  with an exposed buffer tube. 
       
    
    
     DETAILED DESCRIPTION 
       [0042]      FIG. 1  illustrates a stock interface  101  and stock interface attachments  102 ,  103  in accordance with aspects of the embodiments. The stock interface  101  is designed to slip over a CAR buffer tube. An ergonomic attachment  102  and a container attachment  103  are designed to attach to the stock interface. Notice that symmetry allows the stock interface attachments  102 ,  103  to be attached on either the left or right side. Dovetails  104  running longitudinally along the stock interface  101  are designed to mate with matching dovetails  105  on the stock interface attachments. A longitudinally running mounting rail  106  can be used for attaching a stock. Items can be stored in the container interior  107 . 
         [0043]    The particular shape of the illustrated dovetails  104  and matching dovetails  105  form what is known as a captured dovetail. Items using captured dovetails are connected by first aligning the dovetails and then sliding the items into position along the dovetails. Alternatively, a snapping dovetail allows the items to be aligned and pressed together such that the items flex and the dovetails snap together. 
         [0044]      FIG. 2  illustrates a stock interface  101  in accordance with aspects of the embodiments. The dovetails  104  and mounting rail  106  can be seen. The shape of the central opening  201  is seen to match the shape of a CAR buffer tube. 
         [0045]      FIG. 3  illustrates a stock interface  101  and container attachments  103  in accordance with aspects of the embodiments. The dovetails  104  and matching dovetails  105  are designed such that the container attachments  103  snap onto the stock interface  101 . Adhesives or threaded fasteners are not necessary but can be used to ensure robust attachment. A threaded fastener can be passed through a hole in a stock interface attachment and into a threaded hard point on the stock interface  101 . The container attachments  103  can be sealed with a plug or a cork. The container attachments  103  can be produced with one end permanently sealed. 
         [0046]      FIG. 4  illustrates a stock interface  101  and ergonomic attachments  102  in accordance with aspects of the embodiments. The dovetails  104  and matching dovetails  105  are designed such that the ergonomic attachments  102  snap onto the stock interface  101 . Adhesives or threaded fasteners are not necessary but can be used to ensure robust attachment. The ergonomic attachments  102  can produce, when attached to the stock interface  101 , a smooth profile suitable for a good cheek weld as required by most marksmen. 
         [0047]      FIG. 5  illustrates a stylized stock  501  attached to the stock interface  101  in accordance with aspects of the embodiments. The stock  501  illustrated is an under sliding butt stock that can be slid along the mounting rail  106  and be firmly attached in a desired position. A spring can press a pin  502  in the stock  501  against the rail  106  to fix the stock in place. A lever  503  can be used to pull the pin  502  away from the rail  106  to free the stock  501 . The under sliding butt stock  501  can be fixed in place even more firmly when the pin  502  slides into a hole on the under side of the mounting rail  106 . Alternatively, a fixed length stock can be attached to the mounting rail  106 . The fixed length stock can be slipped onto the mounting rail  106  and pressed fully forward. Pins, adhesives, fasteners, tape, hook-and-loop, or interlocking fingers, or other means can be used for securing either adjustable or permanent length stocks. 
         [0048]      FIG. 6  illustrates two container attachments  602  that can be mounted side by side in accordance with aspects of the embodiments. A stock interface  601  has a first and second container attachment  602  mounted side by side. 
         [0049]      FIG. 7  illustrates a power attachment  701  with an electrical power compartment  707  in accordance with aspects of the embodiments. The electrical power compartment  707  is illustrated as containing replaceable batteries  702 , a negative electrode  705 , a conductive spring  703 , and a positive electrode  704 . An electrical interconnect  706  is electrically attached to the positive electrode  704  and, by way of a wire  708 , to the negative electrode  705 . 
         [0050]      FIG. 8  illustrates a high level block diagram of a power attachment  801  with a fuel cell  802  in accordance with aspects of the embodiments. A fuel tank  803  provides fuel to the fuel cell. Those practiced in the art of fuel cells are familiar with fuel cells and the fuels that can be used to power them. An electrical interconnect  804  can be used for passing electrical energy into and out of the power attachment. Those skilled in electrical equipment or electronic systems are familiar with many types of electrical interconnects including electrodes, plug and socket, card edge connectors, inductive couplers, and others. 
         [0051]      FIG. 9  illustrates a high level block diagram of a power attachment  901  with permanent batteries  902  in accordance with aspects of the embodiments. Permanent batteries  902  are a permanent part of the power attachment  901 . As such, the entire power attachment  901  is replaced when the permanent batteries  902  are depleted. Permanent batteries, replaceable batteries, and fuel cells are different types of electrical power source. 
         [0052]      FIG. 10  illustrates a cut view of a stock interface  101  fixedly attached to a CAR buffer tube in accordance with aspects of the embodiments. Fixedly attached means that the stock interface is not adjustable or otherwise free to slide along the CAR buffer tube. The stock interface  101  has been slid into position on the CAR buffer tube. The CAR buffer tube&#39;s elongated rib  1103  has a groove  1201  into which an appropriately sized bolt  1006  is placed. A bolt is appropriately sized if it cannot rotate within the groove  1201 . A fastener  1005 , illustrated here as a bolt, extends through an interface hole  1004  in the stock interface  101  and is threaded into the appropriately sized nut  1006 . An interface hole  1004  with a countersunk portion  1003  is illustrated. Tightening the fastener  1005  causes the fastener  1005  to press into the bottom of the groove  1201  and thereby frictionally attach the stock interface  101  and the CAR buffer tube together. Aligning an interface hole  1004  with a buffer tube hole  1202  can produce a stronger binding between the stock interface  101  and the CAR buffer tube. Elongating the interface hole  1004  can ease alignment. 
         [0053]    Threading the interface hole  1004  with a tap can dispense with the need for an appropriately sized nut  1006  and allow use of a set screw instead of a bolt  1005 . A second set screw tightened into a threaded interface hole behind a first set screw can bind both set screws within the interface hole. Furthermore, a threaded interface hole adapts the stock interface for installation on either a CAR buffer tube or a cylindrical buffer tube. A bolt threaded through the interface hole  1004  presses against the side of the cylindrical buffer tube to cause a frictional attachment. 
         [0054]      FIG. 15  illustrates clamping a stock interface  1501  to a CAR buffer tube  1502  in accordance with aspects of the embodiments. The stock interface  1501  is placed over a CAR buffer tube  1502 . The buffer spring  1503  can be seen inside the CAR buffer tube  1502 . The stock interface  1501  has a bottom gap  1507  and a hole  1504 . The hole end  1505  is threaded so that a bolt  1506  can be inserted into the hole  1504  and tightened. Tightening the bolt  1506  causes the bottom gap  1507  to narrow which also causes the stock interface  1501  to clamp onto the CAR buffer tube  1502 . The clamping action frictionally attaches the stock interface  1501  to the CAR buffer tube  1502 . Multiple holes and bolts can be used along the length of the stock interface  1501  to increase the clamping action and thereby more fixedly clamp the stock interface  1501  onto the CAR buffer tube  1502 . 
         [0055]      FIG. 16  illustrates clamping a stock interface  1601  to a cylindrical buffer tube  1602  in accordance with aspects of the embodiments.  FIG. 16  is similar to  FIG. 15  in that a stock interface  1601  is placed over a buffer tube and frictionally attached by clamping. A cylindrical buffer tube is illustrated to demonstrate that clamping can be used to frictionally attach stock interfaces to either cylindrical buffer tubes or to CAR buffer tubes. The stock interface  1601  has a second gap  1603  that can be narrowed by placing a top bolt  1604  through a top hole  1605  and threading it into the top hole bottom  1606 . Tightening the top bolt  1604  and the bottom bolt  1506  causes a clamping action that frictionally attaches the stock interface  1601  to clamp onto the buffer tube  1602 . 
         [0056]    The top gap  1603  and the bottom gap  1507  can, but need not, run the full length of the stock interface  1601 . A stock interface  1601  with full length gaps can be separated into a threaded side  1607  and a through hole side  1608 . A complete stock interface can be formed from two through hole pieces by placing a nut into the hole  1504  of one through hole piece, placing a bolt into the hole  1504  of the other through hole side piece, and threading the bolt into the nut.