Removable barrel and hand guard for modular rifles

A kit for use with a modular weapon having a barrel and having an upper receiver defining a gas port and a barrel opening. The kit comprises an upper receiver plate for attaching to the upper receiver, and a barrel plate. The weapon barrel passes though concentric openings in the upper receiver plate and the barrel plate and is secured in the opening within the barrel plate. Another opening in the barrel plate receives a primary gas tube such that a rearward segment of the primary gas tube extends rearwardly from that opening and a forward segment of the primary gas tube extends forwardly from that opening. A forward end of a gas tube extension couples to a rearward end of the primary gas tube and a rearward end of the gas tube extension is received within the gas port when the kit is in use with the modular rifle. An assembly removably attaches the upper receiver plate and the barrel plate thereby creating a gas flow path beginning at the gas port and comprising the gas tube extension, the rearward segment of the primary gas tube, and the forward segment of the primary gas tube.

FIELD OF THE INVENTION

A method, system, and kit related to a removable and replaceable barrel and gas tube for modular rifles.

BACKGROUND OF THE INVENTION

M16 and AR15 rifles are air-cooled, gas-operated, magazine-fed assault rifles. These rifles are the primary assault weapons used by military and police forces.

A gas-operated rifle uses a portion of the high pressure gas formed as the ammunition round travels through the barrel to supply energy to operate the auto-loading feature of the rifle. The high pressure gas powers a mechanism to extract the spent casing and chamber a new cartridge. Energy from the gas is harnessed through either a port in the barrel or a trap in the muzzle. This high-pressure gas travels through a gas tube that is located parallel to the barrel and upon exiting the tube impinges on a surface such as a piston head to provide motion for unlocking the action, extracting the spent casing, ejecting the spent casing, cocking the hammer or striker, chambering a fresh cartridge, and finally locking the action.

Such a modular rifle is illustrated inFIG. 1. As shown inFIG. 2, the rifle comprises a lower receiver assembly1conveniently separable from an upper receiver assembly2. The lower and upper receiver assemblies1and2are connected using push pins with the pins carried by the lower receiver assembly1and extending through openings (not visible inFIG. 2) in the upper receiver assembly2.

The lower receiver assembly1contains a lower receiver, fire control components, and a buffer assembly included in the butt-stock. These components are not separately designated inFIG. 2and are not pertinent to the structure and function of the present invention. Instead, the present invention relates generally to the upper receiver assembly2and its components.

Prior artFIG. 3illustrates the upper receiver assembly2, comprising an upper receiver3and a hand guard4surrounding a barrel5. The barrel5is affixed to the upper receiver3using a barrel nut that is obscured from view inFIG. 3but shown inFIG. 4.

Prior artFIG. 4illustrates the upper receiver assembly2with the hand guard4removed to expose a barrel nut6, a stock gas tube7and a gas block8that holds the stock gas tube7in place. The barrel5and the gas block8each define a small opening through which gas passes from the barrel, through the gas block, and into the stock gas tube7.

In the prior art modular rifles ofFIGS. 1-4, the barrel5is affixed to the upper receiver3with the barrel nut6and this arrangement requires specialized tools and fixtures to remove and attach the barrel. For example, if the user wishes to change to a barrel of a different length. The prior art design makes it nearly impossible to remove the barrel in the field without use of these tools. Removal also requires a significant amount of time and familiarity with intricate mechanisms of the rifle.

DETAILED DESCRIPTION OF THE INVENTION

Before describing in detail the particular methods and apparatuses related to a removable barrel and hand guard for modular rifles, it should be observed that the present invention resides primarily in a novel and non-obvious combination of elements and process steps. So as not to obscure the disclosure with details that will be readily apparent to those skilled in the art, certain conventional elements and steps have been presented with lesser detail, while the drawings and the specification describe in greater detail other elements and steps pertinent to understanding the inventions.

The presented embodiments are not intended to define limits as to the structures, elements or methods of the inventions, but only to provide exemplary constructions. The embodiments are permissive rather than mandatory and illustrative rather than exhaustive.

The components of the present invention when installed in a rifle allow the rifle user to easily and quickly remove the barrel without specialized tools and replace the removed barrel with a barrel of a different length. As is known by those skilled in the art, a longer barrel allows the ammunition round to exit the barrel with a greater velocity and thus travel farther (i.e., have a longer range) than a round shot from a shorter barrel.

Advantages of the present invention include at least: allowing the rifle barrel to be easily removed to store or transport the rifle in a smaller space; allowing the user to easily remove and replace the barrel with a different length barrel; allowing conversion of the rifle to a different caliber; and, simplifying cleaning of the weapon as specialized tools are not required to disassemble the rifle. With regard to different barrel lengths, a sniper prefers a longer rifle barrel while a shorter barrel is desired in close quarter combat.

The invention also permits the user to use any one of many different available hand guards. Alternatively, the barrel coupler of the present invention may be supplied with a hand guard permanently integrated with the barrel coupler. In this latter embodiment the barrel and hand guard can both be removed from the rifle as one unit without the user of tools.

The components of the present invention may be installed on any rifle or weapon having an appropriately styled barrel and receiver interface.

The components of the invention may also be considered a kit for adding and/or replacing the components of an existing rifle to allow the user to then easily and conveniently exchange a barrel of a first length for a barrel of a second length. The kit components can be installed on an existing rifle without any permanent modifications to the rifle. Alternatively, certain of the invention components can be integrated into a new rifle as it is manufactured, e.g., the upper receiver coupler integral with the upper receiver and/or the barrel coupler integral with the barrel.

The components of the invention generally comprise: an upper receiver coupler for attaching to an upper receiver of an existing rifle and a barrel coupler for attaching to a barrel of the existing rifle. The upper receiver coupler and the barrel coupler are removably joined or latched together using components attached to the upper receiver coupler, to the barrel coupler, and/or to both. Further, the invention comprises a novel gas tube that is attached to the barrel, passes through the upper receiver coupler and the barrel coupler, and via a gas tube extension attaches to the rifle upper receiver.

FIG. 5is an exploded view illustrating an upper receiver coupler100and a barrel coupler103and their associated components. With the upper receiver coupler attached to the upper receiver, as described elsewhere herein, and the barrel coupler attached to the barrel, as described elsewhere herein, coupling the upper receiver coupler and the barrel coupler thereby attaches the barrel to the upper receiver to form a continuous path for the ammunition round.

Additionally, when the upper receiver coupler and the barrel coupler are joined, a gas tube running parallel to the barrel extends from a forward end of the barrel, passes through both couplers, and is received within the upper receiver of the rifle. Gas flowing through this path actuates various rifle functions as described above.

Turing toFIG. 6, it illustrates the conventional upper receiver3further comprising a threaded upper receiver extension3A and a gas port3B. In a prior art rifle, the barrel is received within the upper receiver extension3A and a barrel nut (not shown) holds the barrel within the upper receiver extension. A groove3C receives a tab on the barrel (not shown) to properly align the barrel to the upper receiver.

With reference toFIGS. 5, 6, and 7, to attach the upper receiver coupler100to the upper receiver3, the threaded upper receiver extension3A is inserted into an opening10A defined in an upper receiver plate10. Internal threads11A of a star nut11threadably engage external threads of the upper receiver extension3A, and the star nut11is tightened to fixedly join the upper receiver coupler100to the upper receiver3.FIG. 7illustrates the final configuration.

Semicircular grooves16in an outer circumference of the star nut11receive mating protrusions of a tool (not shown) for tightening the star nut11. However, this feature is not a required element of the invention instead it is merely a convenient technique for tightening the star nut11.

FIG. 8also illustrates certain components and features of the upper receiver coupler100including the upper receiver plate10and the star nut11. The remainder of the illustrated components are described below.

In an alternative embodiment, in lieu of using the star nut11, the upper receiver plate10comprises internal threads25(seeFIG. 24) that threadably engage mating threads3D on the upper receiver extension3A ofFIG. 6.

With reference toFIGS. 5 and 9, to position the barrel5within the barrel coupler103, the barrel is received within an opening103A that extends through the barrel coupler. A raised segment of the barrel, referred to as a collar (see a collar5A inFIGS. 9, 11, and 12), is disposed within the opening103A and a rear surface of the collar5A abuts an internal surface of the barrel coupler103.

With continued reference toFIGS. 5 and 9, set screws17distributed around a circumference of a barrel plate14are urged against the barrel5to hold the barrel within the barrel coupler103. In one embodiment the set screws are spaced at 120 degrees although only one set screw17is illustrated inFIG. 5. Additionally, when the barrel coupler and the upper receiver coupler are mated, the barrel flange is captured and held in place between the mated barrel coupler and the upper receiver coupler. Also, in one embodiment the groove3C of the upper receiver extension3A ofFIG. 6receives a tab (not shown) of the barrel to align the barrel in the upper receiver. Finally, the mated couplers exert additional forces on the barrel to secure the barrel within the barrel coupler.

As can be seen inFIG. 9, a barrel segment5B of the barrel5extends beyond a rear surface of the barrel coupler103. The barrel segment5B extends into the opening10A (seeFIGS. 5, 7, and 8) of the coupler plate10when the upper receiver coupler and the barrel coupler are mated.

In lieu of using the set screws17, the barrel can be held in place within the barrel coupler103by a compression fitting comprising a slot defined in the barrel plate14and a tension screw to close the slot after the barrel is inserted. Alternatively, an end of the barrel comprises a split cone feature with an outside-threaded nut for threading into mating threads extending from a rear surface of the barrel plate.

Returning toFIG. 5, in addition to the barrel plate14, the barrel coupler103further comprises hooks12, levers13for operating the hooks12, and a barrel plate extension14A. Only one hook12and lever13is illustrated inFIG. 5as the opposing hook and lever is not visible inFIG. 5.

The hooks12and levers13are held together by pins not illustrated inFIG. 5but depicted as a pin140inFIGS. 22 and 23. With reference toFIG. 5, the pin is held in position by a set screw22, again, with only one illustrated inFIG. 5.

With the barrel coupler103in contact with the upper receiver coupler100, exerting an inwardly-directed force on the levers13forces the hooks12to each engage a hardened pin21within each recess10B in the upper receiver plate10. This action locks the barrel plate14to the receiver plate10and thereby locks the barrel coupler103to the upper receiver coupler100. Another hook, lever, recess and pin are disposed on an opposing side of the respective barrel plate and the upper receiver plate and thus are hidden from view inFIG. 5.

The illustrated pin21is held in position by action of a set screw23.

With the barrel5attached to the barrel coupler103with the set screws17, the barrel coupler103attached to the upper receiver coupler100with the hooks12, and the upper receiver coupler attached to the upper receiver3with the star nut11, the barrel is thereby coupled to upper receiver to provide a path for the round as it exits the upper receiver, enters and passes through the barrel segment5B (seeFIG. 9) and the barrel5, and exits from a forward end of the barrel5.

With this invention the barrel5can be easily and quickly changed by operating the levers13to release the hooks12and thereby separate the upper receiver coupler100from the barrel coupler103and loosening the set screws17. This operation is much simpler than the required operations to remove the barrel in a prior art rifle.

With reference toFIG. 5, when the barrel coupler103is brought into contact with the upper receiver coupler100, an alignment pin19extending rearward from a rear surface of the barrel plate14is received within an opening20in a front surface of the upper receiver plate10for aligning the upper receiver coupler100and the barrel coupler103.

FIG. 10is a rear view of the barrel coupler103. In particular, this view shows an opening29through which a primary gas tube33passes, as described below.

As described above, a gas-operated rifle uses some of the high pressure gas generated as the ammunition round travels through the barrel to supply energy to operate the auto-loading feature of the rifle. In the present invention, a high pressure gas path extends from an entry point of the gas tube on the barrel5, along the barrel, through the barrel coupler103, through the upper receiver coupler100and finally to the upper receiver3.

As can be seen inFIGS. 5 and 9, a primary gas tube33extends forward from the barrel plate14runs parallel to the barrel5and connects to the barrel5at the gas block8.

Working toward the butt stock of the rifle and beginning at the barrel plate14, the primary gas tube33passes through the opening29(seeFIG. 10) in the barrel plate14. A rearward segment33A of the primary gas tube33(seeFIGS. 5 and 9) extends rearward out from the opening29in the barrel plate and through an opening36(seeFIG. 8) in the receiver plate10. An end33B of the rearward segment33A mates with a coupler34(that is, when the upper receiver coupler100and the barrel coupler103are coupled) that is in turn connected to a gas tube extension35(seeFIGS. 5 and 8).

To avoid interference between the rearward segment33A of the primary gas tube33and the upper receiver coupler100and its associated components, the rearward segment33A is disposed within one of the semicircular grooves16of the star nut11.

An end35A of the gas tube extension35(both of which are depicted inFIG. 5) is received within the gas port3B of the upper receiver3as illustrated inFIG. 6.

FIG. 11illustrates the barrel5with a stock or stock gas tube7installed in the gas block8.

FIG. 12illustrates the barrel5with the shortened primary gas tube33, i.e., shorter than the stock gas tube7, installed in the gas block8. The shortened gas tube is required due to presence of the receiver coupler100and the barrel coupler103in the gas flow path between the gas block8and the gas port3B in the upper receiver3.

FIG. 13illustrates the hand guard4as mated with the barrel coupler103and covering a segment of the barrel5and the entire length of the primary gas tube33. To attach the hand guard4, inside threads of the hand guard threadably engage outside matching threads of the barrel plate extension14A depicted at least inFIGS. 5 and 9.

FIG. 13also reveals that the hand guard4and the barrel5, when affixed to the barrel coupler103, can be removed from the rifle as a unitary structure by simply separating the barrel coupler103from the upper receiver coupler100.

FIG. 14illustrates the upper receiver coupler100(and certain ones of its attached components) in position to mate with the barrel coupler103(and certain ones of its attached components).

To mate the upper receiver coupler100and the barrel coupler103, (seeFIGS. 5 and 14in particular) the opening10A in the upper receiver plate10is aligned with the barrel segment5B, the pin19of the barrel coupler is aligned with the opening20in the receiver coupler, and the rearward segment33A of the gas tube is aligned with the coupler34. The upper receiver coupler and the barrel coupler are brought into contact and by the application of an inwardly directed force on the levers13, the hooks12on the barrel coupler are locked around the pins21in the recesses10B of the upper receiver coupler.

FIG. 15illustrates the mated upper receiver coupler100and the barrel coupler103with the hooks12in an open position.

FIG. 16illustrates the coupled upper receiver coupler100and the barrel coupler103with the hooks12in a closed position.

FIG. 17illustrates an AR15/AR10110depicting the upper receiver coupler100and the barrel coupler103of the present invention.

FIG. 18illustrates another embodiment of the present invention comprising an upper receiver coupler111for mating with a barrel coupler113. The upper receiver coupler111defines recesses120each for receiving a hook122(in lieu of the hook12of other embodiments) to attach the upper receiver coupler111to the barrel coupler113.

Each hook122comprises a head130affixed to a shaft132at a first end thereof. A second end of the shaft132terminates in a ring133concentrically mounted on a pin136that is in turn attached to or captured within a barrel plate137. The hooks122are pivoted into the recesses120to lock the upper receiver coupler111and the barrel coupler113together.

Pivoting of the hooks122out of the recesses120permits separation of the upper receiver coupler111and the barrel coupler113. Only one of the hooks122is depicted in its entirety inFIG. 18, another hook122and its associated components is hidden from view inFIG. 18.

In one embodiment the head130threadably engages mating threads (not shown) on the shaft132. The coupling force exerted by the hook122on the upper receiver coupler111is adjusted by turning the head130on the mating threads of the shaft132.

FIG. 19illustrates a stock gas tube7.FIG. 20illustrates the shortened primary gas tube33connected to the gas tube extension35for use with the couplers of the present invention.FIG. 21illustrates an exploded view of the primary gas tube33and the gas tube extension35.

FIG. 22is a close-up view of the hook12and the lever13including a pivot pin140and a tension adjustment screw142. Turning the screw142adjusts (increasing or decreasing) the force exerted by the hook12for holding the upper receiver coupler100and the barrel coupler103together and for increasing or decreasing the distance between the two couplers.

FIG. 23depicts the hook12, the pivot pin140and the tension adjustment screw142.

Because the components of the present invention can be added to an existing rifle without modifying the existing rifle, these components can be easily removed and the rifle returned to its original configuration whenever desired. This is an advantage to the rifle owner who may wish to sell or trade-in a rifle that has been modified to implement the features of the present invention.

While the invention has been described with reference to various embodiments, it will be understood by those skilled in the art that various changes may be made and equivalent elements and process steps may be substituted for elements and steps thereof without departing from the scope of the present invention. The scope of the present invention further includes any combination of the elements and process steps from the various embodiments set forth herein. In addition, modifications may be made to adapt a particular situation to the teachings of the present invention without departing from its essential scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.