Field of the Invention
The present invention relates generally to firearms, namely semi-automatic firearms, such as the M-16 and M-4 tactical rifles of the military and law enforcement and AR-15 tactical rifles that are widely used for sporting and match shooting activities. These firearms utilize a portion of the cartridge gas pressure that is generated within a rifle barrel upon cartridge firing to operate a mechanism for cartridge case extraction, ejection and fresh cartridge pickup and chambering. More particularly, the present invention concerns a gas block that is mounted to a rifle barrel at one or more barrel ports and defines a receptacle that receives and retains an end portion of a gas conducting tube member, permitting cartridge gas pressure received by passages of the gas block member from a barrel port to be conducted to a bolt carrier and bolt for pressure energized operational movement of the bolt carrier and bolt. Even more specifically the present invention concerns sealing apparatus for establishing a positive gas seal at the juncture of the gas conducting tube and the gas block.
Description of the Prior Art
M-16, M-4 and AR-15 tactical rifles are typically provided with a gas block member which has a tubular portion that receives a portion of a gun barrel and is positioned such that a gas conducting passage system of the gas block is in gas receiving communication with one or more holes or gas ports that intersect the bore of the barrel. When the rifle is fired, a portion of the cartridge gas is vented to gas conducting passage system from the rifle bore and is employed for gas pressure actuation of the cartridge handling system of the rifle. A gas conducting tube member that engages within a gas tube receptacle of the upper receiver of the firearm has an end portion that is retained within a gas tube receptacle of the gas block. The end portion of the gas tube is typically prepared to establish a relatively close fit within the gas tube receptacle. However, it has been determined that gas leakage often occurs at the gas tube/gas block interface. This gas leakage can dissipate some of the cartridge gas pressure in the gas handling system and interfere with proper gas energized operation of the bolt carrier and bolt mechanism, potentially preventing optimum operational characteristics of the firearm. Moreover, the hot, high pressure cartridge gas progressing within the gas block and gas conducting tube tends to be erosive, thus causing any gas leakage condition to worsen as the duration of firearm use progresses.
It is a principal feature of the present invention to provide a novel positive cartridge gas sealing system for the gas block and gas tube to ensure that cartridge gas leakage at the gas tube/gas block interface is prevented during firearm use.
It is another feature of the present invention to provide a novel gas block and gas conducting tube for a semi-automatic or automatic firearm that positively prevents gas leakage at the gas block/gas conducting tube interface during firing activity and thus ensures that the resulting cartridge gas is employed as efficiently as possible for operation of an autoloading firearm according to its technical design, promoting firearm efficiency, accuracy and control.
Briefly, the various objects and features of the present invention are realized by the provision of an autoloading firearm having a gas block that is mounted along the length of its firearm barrel in alignment with a gas passage that is in communication with the gas port of the barrel. The gas block defines a gas tube receptacle and further defines a gas tube seal receptacle that is located about the gas tube receptacle. A gas conducting tube is secured within the gas tube receptacle of the gas block by means of a retainer member that engages within aligned holes of the gas tube and gas block.
A deformable annular sealing ferrule is positioned about an end portion of the gas conducting tube and is press-fitted within the gas tube seal receptacle. During the press-fitting operation the gas tube sealing ferrule is deformed and establishes positive surface to surface sealing with the outer cylindrical surface of the gas conducting tube and with the internal surface geometry of the gas tube receptacle. The gas tube sealing ferrule prevents any cartridge gas leakage at the juncture or interface of the gas conducting tube and gas block.
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the preferred embodiment thereof which is illustrated in the appended drawings, which drawings are incorporated as a part hereof.
It is to be noted however, that the appended drawings illustrate only a typical embodiment of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
In the Drawings:
Referring now to the drawings and first to
At a desired location along the length of the barrel 12 a gas block 20 is mounted in substantially fixed relation with the barrel, being secured about the external surface of the barrel by means of set screws or any other suitable retainer or locking devices. As shown in the longitudinal section view of
A conventional gas conducting tube 31 has an end portion thereof located in within the gas tube receptacle 28 and defines a gas passage 33 that serves to conduct the cartridge gas pressure from the gas block to a bolt carrier and bolt actuating mechanism of the firearm. Cartridge gas communication with the gas port becomes effective, after a bullet has moved past the gas port 24 or ports 24 and 25, for the purpose of driving the bolt carrier and bolt rearwardly against the force of a bolt return or buffer spring. This rearward bolt carrier and bolt movement extracts a spent cartridge case from the cartridge chamber of the barrel and ejects the spent cartridge case and prepares the bolt carrier and bolt mechanism for spring urged forward movement of a fresh cartridge from a cartridge magazine into the cartridge chamber of the barrel. The gas tube 31 is secured within the gas tube passage 28 by a gas tube retainer 29 that extends through aligned retainer openings in the gas block 20 and gas tube 31. The gas tube retainer 29 is preferably in the form of a retainer pin, but if desired may have the form of a retainer screw or any other suitable type of retainer that secures the gas tube in substantially immoveable relation with the gas block member 20.
The barrel 12 of the firearm is machined to define a reduced diameter external cylindrical section 30 about which the gas block 20 is received. The barrel structure is also machined to define a gas passage 32, best shown in
Referring now to
The upper portion of the gas block is also defined by a boss or thickened section 50 which is drilled or otherwise machined to define a gas tube bore 52 within which the rear end section of the gas conducting tube 31 is received. Holes 54 are formed in the gas tube, as shown in
With reference to
Sealing Ferrule Installation: When connection of the gas conducting tube 31 with the gas block 20 is initiated, the gas sealing ferrule 60 is positioned over the gas tube 31 and is moved to a desired position along the length of the gas tube. The rear end portion of the gas tube is then inserted into the counter-bored seal receptacle 58 with its gas communication port 35 aligned with the gas passage 32 of the gas block. A retainer pin, screw or other suitable retainer is then inserted through the aligned holes 54 and 56 of the gas conducting tube and gas block to retain the gas conducting tube in assembly within the tube receptacle of the gas block. The gas sealing ferrule 60 is moved into the counter-bored seal receptacle 58 to establish positive gas sealing with the internal surfaces that define the seal receptacle 58 and with the gas conducting tube 31. The tapered annular lead end 66 of the gas sealing ferrule serves to guide the cylindrical portion of the gas seal ferrule into the counter-bored seal receptacle 58. When inserted to its full extent within the counter-bored seal receptacle 58 the annular tapered lead end of the gas sealing ferrule can come into contact with the annular internal stop shoulder 59, thus stopping linear insertion movement of the gas sealing ferrule and assisting in deformation of the gas sealing ferrule to establish positive sealing. The press-fitting operation also causes the circular flange 72 to enter its circular recess 70 and contact the outwardly facing annular shoulder 71, thus limiting further linear movement of the sealing ferrule during its press-fitting operation.
Typically press-fitting of the gas sealing ferrule 60 may be accomplished by placing the gas block 20 within a fixture and using a press to move the gas sealing ferrule linearly along the gas tube and into the seal receptacle with sufficient force for press fitting the gas sealing ferrule. The press-fitting activity typically causes slight deformation of the material from which the gas sealing ferrule is composed and causes it to establish positive surface to surface sealing engagement with both the seal receptacle 58 and the outer cylindrical surface of the gas conducting tube 31. Thus, when the firearm is subsequently fired, the high gas pressure of the resulting cartridge gas will be contained against any possibility of leakage at the gas block and gas tube interface as the cartridge gas pressure traverses the gas conducting tube and increases the pressure within the gas passages of the upper receiver of the firearm. Virtually all of the cartridge gas pressure that is generated upon cartridge firing is employed for bolt and bolt carrier operation and cartridge cycling.
From the foregoing description and drawings it is evident that the present invention is one well adapted to attain all of the objects and features hereinabove set forth, together with other objects and features which are inherent in the apparatus
As will be readily apparent to those skilled in the art, the present invention may easily be produced in other specific forms without departing from its spirit or essential characteristics. The present embodiment is, therefore, to be considered as merely illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.