Adjustable gas system for cartridge gas actuated firearms

Abstract

A propellant gas energized firearm has a gas supply passage conducting propellant gas from a gas port of a firearm barrel to an actuating chamber of a bolt carrier and bolt group having an actuating chamber. A gas key member is mounted to the bolt carrier and defines a part of the gas supply passage and has an opening intersecting the gas supply passage. A gas adjustment member is selectively moveable within the gas adjustment opening and has a gas interruption member projecting into the gas supply passage. The gas adjustment member is rotatable within the gas adjustment opening for selectively positioning the gas interruption member within the gas supply passage to selectively control the characteristics of the propellant gas delivery to the actuating chamber of the bolt carrier and bolt group.

Claims

1. A propellant gas energized firearm having an auto-cycle mechanism, comprising: a firearm barrel having a gas port located along the length thereof; a gas block being mounted externally of said firearm barrel and having a propellant gas passage in gas receiving communication with said gas port; a receiver within which a gas energized bolt carrier and bolt are disposed for gas energized cycling movement, said bolt carrier defining a bolt passage having a bolt member movably positioned therein and having a gas supply port in communication with said bolt passage; a gas key member defining a gas supply passage extending from said propellant gas passage of said gas block to said gas supply port of said bolt carrier; and a gas adjustment member being movably mounted to said gas key member and having a gas interruption portion thereof positioned for selective adjustment within said gas supply passage to selectively control propellant gas propagation through said gas supply passage and into said internal bolt passage of said bolt carrier; a curved outer surface and a generally planar surface being defined by said gas interrupting portion; a broad smoothly contoured curved surface establishing intersection with said curved outer surface and said generally planar surface; a sharp edge establishing intersection with said curved outer surface and with said generally planar surface; and said gas adjustment member being rotatable to selectively locate said curved outer surface, said broad smoothly contoured curved surface, said generally planar surface and said sharp edge within said gas supply passage and thereby select propellant gas flow and pressure and establish desired propellant gas conditions within said gas chamber and selectively control bolt carrier and bolt actuation.

2. The propellant gas energized firearm of claim 1, comprising: said gas key member being mounted to said bolt carrier and defining a portion of said gas supply passage; said gas key member defining a gas adjustment receptacle in communication with said gas supply passage; and said gas adjustment member being received within said gas adjustment receptacle and having said gas interruption portion being an integral portion thereof positioned within said gas supply passage and being selectively rotatably positioned within said gas supply passage for control of propellant gas energization of said bolt carrier and bolt member.

3. The propellant gas energized firearm of claim 1, comprising: said bolt carrier defining a bolt key mount; said bolt key member having a portion of said gas supply passage therein; said bolt key member defining said gas adjustment receptacle; and said gas adjustment member being rotationally mounted within said gas adjustment receptacle for selective flow adjusting movement within said gas adjustment receptacle and having said gas interruption portion projecting into said gas supply passage and being selectively rotatably positioned to establish desired variations in gas flow characteristics.

4. The propellant gas energized firearm of claim 1, comprising: said gas adjustment member defining an axial center-line; and said gas interruption portion being positioned eccentrically with respect to said center-line.

5. The propellant gas energized firearm of claim 1, comprising: said gas key member mounted in substantially fixed relation with said bolt carrier and having an angulated tubular section defining a portion of said gas supply passage, said angulated tubular section having an internally threaded opening intersecting said gas supply passage; and said gas adjustment member having an externally threaded section being positioned within said internally threaded opening and having said gas interruption portion extending into said gas supply passage and being selectively positionable within said gas supply passage to selectively position said curved outer surface, said generally planar surface and said sharp edge in selectively oriented relation within said gas supply passage and adjust the flow of propellant gas through said gas supply passage and achieve desired changes in the propellant gas being supplied to and acting on said auto-cycle mechanism of the firearm upon firing of a cartridge.

6. The propellant gas energized firearm of claim 1, comprising: said gas adjustment member defining an axial centerline; and said gas interruption portion being eccentrically located with respect to said axial centerline and having a plurality of surface and edge geometries that are selectively positioned relative to propellant gas flow within said gas supply passage to control propellant gas flow and pressure to said auto-cycle mechanism.

7. A propellant gas energized firearm, comprising: a firearm barrel having a gas port located along the length thereof; a gas block being mounted externally of said firearm barrel and having a propellant gas passage in gas receiving communication with said gas port; an auto-cycle mechanism having a gas energized bolt carrier and bolt and a gas receiving actuation chamber being exposed to both said bolt carrier and said bolt; a propellant gas supply conduit conducting propellant gas from said gas block to gas receiving actuation chamber; a gas key member being mounted to said bolt carrier and having an internal gas supply passage conducting propellant gas to said gas receiving actuation chamber, said gas key member having an angulated tubular section defining a portion of said internal gas supply passage and having an internally threaded gas adjustment receptacle in communication with said internal gas supply passage within said angular tubular section; and a gas adjustment member having an externally threaded section being threaded and rotationally positionable within said internally threaded gas adjustment receptacle of said gas key member and having a gas interrupting member projecting therefrom and having a curved surface and an intersecting generally planar surface defining an intersecting edge being positioned for selective gas flow adjustment within said gas supply passage to selectively control the characteristics of propellant gas being conducted through said internal gas supply passage and into said gas receiving actuation chamber of said bolt carrier.

8. The propellant gas energized firearm of claim 7, comprising: said gas key member being mounted to said bolt carrier and having an angulated tubular section defining a portion of said gas supply passage; said angulated tubular section of said gas key member defining said gas adjustment receptacle and being in communication with said gas supply passage within said angulated tubular section; and said gas adjustment member being secured by threaded engagement within said gas adjustment receptacle and having said gas interruption member positioned for rotational adjustment within said gas supply passage section of said angulated tubular section of said gas key member and selectively rotationally positioning said curved surface, said intersecting generally planar surface and said intersecting edge within said gas supply passage for selectively adjusting propellant energized pressure and flow control of propellant gas and causing selective energization of said bolt carrier and bolt member during auto-cycling activity of said firearm.

9. The propellant gas energized firearm of claim 7, comprising: said gas adjustment member defining an axial center-line; and said gas flow interrupting member projecting from said gas adjustment member being positioned eccentrically with respect to said axial center-line and being rotatable within said gas supply passage about said axial center-line.

10. The propellant gas energized firearm of claim 7, comprising: said gas adjustment member being a one-piece member and extending into said gas supply passage of said angulated tubular section, being selectively rotationally positionable within said gas supply passage to adjust the flow of propellant gas through said gas supply passage and achieve desired changes in the pressure and flow characteristics of the propellant gas being supplied to and acting on said auto-cycle mechanism of the firearm upon firing of a cartridge.

11. The propellant gas energized firearm of claim 10, comprising: said gas interrupting member being selectively rotatable to position said curved surface, said generally planar surface or said intersecting edge selectively within said gas supply passage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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.

(2) 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.

(3) In the Drawings:

(4) FIG. 1 is a side elevation view showing a propellant gas actuated tactical rifle that represents the prior art to which the adjustable propellant gas system of present invention is directed;

(5) FIG. 2 is a partial section view showing the upper and lower receiver assemblies of the firearm of FIG. 1 and further showing the bolt carrier, bolt assembly and adjustable gas key mechanism in relation to the cartridge case of a cartridge in seated position with the bolt member;

(6) FIG. 3 is an exploded illustration showing a bolt carrier group of a tactical firearm wherein a gas key having a propellant gas adjustment member is shown with retainer screws for retained attachment of the gas key to the bolt carrier;

(7) FIG. 4 is a schematic isometric illustration showing a portion of the gas key member of FIG. 3 and showing the position of the gas adjustment member relative to the structure of the gas key member;

(8) FIG. 5 is a top plan view showing the gas key member of FIGS. 3 and 4 showing the gas key member and showing the adjustment head structure of the propellant gas adjustment member;

(9) FIG. 6 is a longitudinal section view taken along line 6-6 of FIG. 5; and

(10) FIG. 7 is an isometric illustration showing the propellant gas adjustment member in detail.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

(11) Referring now to the drawings and first to FIGS. 1 and 2, a tactical rifle type firearm representing the prior art is shown generally at 10 and incorporates a lower receiver assembly 12 having a butt-stock assembly 14. The firearm 10 also incorporates an upper receiver assembly 16 that is pivotally connected with the lower receiver 12 by a pivot pin 18 that extends through a pivot opening 20 of a pivot projection 22 that extends downwardly from a forward portion of the upper receiver assembly 16. The upper and lower receiver assemblies are further secured in assembly by a locking pin 24 that extends through the frame portion of the lower receiver assembly and extends through a locking aperture 26 that is defined by a locking projection 28 that extends downwardly from the rear portion of the upper receiver assembly 16.

(12) It should be borne in mind that the upper and lower receiver assemblies can be simply and easily separated by removing the pivot pin 18 and the locking pin 24 or moving them to inactive positions. The pivot pin and locking pin are both accessible externally of the lower receiver member 12. The pivot pin and locking pin are typically movable to release positions with the use of a simple tool, such as a punch or pin. Disassembly of the upper and lower receiver assemblies is often done, both in servicing facilities and in the field, for the purpose of cleaning and servicing this type of tactical firearm. With the locking pin 24 moved to its release position the upper and lower receivers may be pivoted so as to expose internal components for simple and efficient cleaning.

(13) Referring now particularly to the section view of FIGS. 2 and 6, a gas tube member 30 extends rearwardly from a gas block that is mounted to the gun barrel of the firearm and receives propellant gas via a gas port in the barrel. The forward end portion of the gas tube 30 is received within a tubular gas tube receptacle 32 that is defined by a tubular member 34 projecting forwardly from a gas key member 36. As shown best in FIG. 6, the forward end of the gas tube 30, shown away from the gas tube, is typically provided with a small, generally cylindrical seal section 31 that establishes sealing engagement with the inner surface of the tubular gas tube receptacle 32. The gas tube member 30 is capable of being inserted into and withdrawn from the gas tube receptacle, thereby permitting simple and efficient disassembly of the barrel assembly of the firearm from the upper receiver assembly.

(14) The gas key member 36 is secured within a gas key seat 37 of a bolt carrier member 38. The bolt carrier member is located for guided linear movement within a bolt carrier chamber of the upper receiver assembly 16 of the firearm 10. The rear end of the bolt carrier member 38 is in engagement with a buffer mechanism, having a buffer spring that is additionally spring loaded by the force of propellant gas during gas energized rearward movement of the bolt carrier and serves to drive the bolt carrier forward upon dissipation of propellant gas pressure acting on the bolt carrier member.

(15) A pair of retainer screws 40 extend through screw openings 41 of the gas key member 36 and are received by threaded screw holes 42 of the bolt carrier member 38, thus securing the gas key member 36 in substantially fixed assembly with the bolt carrier member. The gas key member 34 defines a gas supply passage 44 that is in communication with the gas tube receptacle 32 and is also in communication with a gas port 46 that is defined in the wall structure 48 of the bolt carrier member. The gas port 46 serves to conduct propellant gas into a bolt chamber 50, within which a rearward portion of a bolt member 52 is received. The space between the rear portion of the bolt member and an inner wall of the bolt carrier constitutes a propellant gas chamber 53 that is in communication with a gas supply port 55 that is aligned with the angulated gas supply passage 87 of the gas key member 36. Thus, propellant gas pressure communicated into the propellant gas chamber 53 acts on the forward end of the bolt carrier, moving the bolt carrier rearwardly and on the rear end of the bolt member, moving the bolt member forwardly within the bolt chamber 50.

(16) The relation of the bolt carrier member and bolt member 52 is best understood with reference to the exploded illustration of FIG. 3. According to FIG. 3, the bolt member 52 has a rearward projection 54 having a seal carrier section 56 that provides support for a plurality of gas ring members 57 that effect a dynamic seal with an internal sealing surface 58 of the bolt carrier member. An extractor member 60 is pivotally mounted to the bolt member by an extractor pin 62 and is urged in one pivotal direction about the extractor pin by means of an extractor spring 64 that is positioned by an extractor spring insert 66. A cartridge base engaging member 67 of the ejector member engages within the circular groove of a cartridge case so that rearward movement of the bolt member causes extraction of a spent cartridge case from the cartridge chamber of the barrel of the firearm. Cartridge extraction is enhanced by the presence of propellant gas pressure that tends to drive the spent cartridge rearwardly, thus essentially loosening the cartridge case within the cartridge chamber of the firearm barrel. At the time the spent cartridge case is loosened, but not yet extracted from the cartridge chamber, the propellant gas pressure will have decreased essentially to zero so that virtually no propellant gas is liberated from the cartridge chamber.

(17) Positioning of the extractor member is also controlled by an extractor roll pin 68. An ejector member 70 is movably secured to the bolt member, with its movement being controlled by an ejector spring 72. A firing pin 71 is located within a central passage of the bolt member with a forward portion projecting through a bolt passage opening 73. Seal rings 69 are carried by the firing pin and establish a seal within a firing pin passage of the bolt member. During extraction of a spent cartridge case, the rearwardly moving cartridge case contacts an ejector member and begins to pivot the cartridge case toward a cartridge case ejection port of the upper receiver and the cartridge case comes into contact with angulated receiver structure which causes ejection of the spent cartridge case through the ejection port of the upper receiver of the firearm.

(18) The cam-pin 14 has a generally cylindrical pin member 76 that extends through a cam-pin opening 77 of the bolt carrier member 38 and engages within a position control recess 78 of the bolt member 52. The cam-pin ensures rotation of the bolt member to its locked position when the bolt member is near its forward most position, causing multiple locking lugs of the bolt head to establish locking engagement within the locking recess adjacent the cartridge chamber. Thus, upon firing of a cartridge the initial presence of high pressure propellant gas acting through the cartridge case on the bolt member will be resisted by the locked condition of the bolt locking mechanism until such time that propellant gas has actuated the bolt carrier and bolt group for unlocking and retraction. The cam-pin 74 also reacts within the cam-pin slot 76 of the bolt carrier during gas energized rearward bolt carrier movement and causes unlocking rotation of the bolt member as the bolt carrier member is moved rearwardly to facilitate bolt unlocking and retraction.

(19) As mentioned above, an important feature of the present invention is the selective control of propellant gas actuation of the bolt carrier member by selective positioning of a gas pressure and flow control adjustment member 80 within a propellant gas supply passage 86 that extends from the gas block of the firearm barrel to the bolt carrier. Preferably the gas pressure control adjustment member 80 is mounted to an angulated section 85 of the gas key member 36, as best shown in FIGS. 5 and 6, and has a gas interruption member 94 that projects into the angulated gas supply passage section 87 that can be selectively positioned to alter or set propellant gas propagation to alter or set the characteristics of propellant gas entering a gas receiving chamber within the bolt carrier. The gas key member 36 is mounted to the bolt carrier member 38 by retainer screws 40 that are received by screw holes 41 of the mounting base portion 37 of the gas key member.

(20) The gas interrupting member 94 is selectively and rotatably positionable within the gas supply passage section 87 cause changes in the pressure and flow characteristics of the gas pressure that is delivered to a gas pressure chamber within the bolt carrier for selectively controlling the timing of the cartridge handling, firing and extraction mechanism of the firearm, which is typically referred to as the bolt carrier and bolt group. It is to be borne in mind that a propellant gas adjustment member may be located at any selected location along the length of the gas supply passage 84 from the gas block to the bolt carrier or within the bolt carrier itself without departing from the spirit and scope of the present invention.

(21) The gas key member 36 defines an internally threaded receptacle 82 that intersects and establishes communication with the inclined or angulated portion 85 of the gas supply passage 86 of the gas key member. The gas pressure control adjustment member 80 has an externally threaded section 88 that is engaged within the internally threaded receptacle 82, with the internal and external threads having a rather tight fit that requires significant manual force for movement of the gas pressure control adjustment member 80 in either rotating direction and prevents the gas pressure control adjustment member 80 from being inadvertently rotated by the shock forces and/or thermal changes that occur as the firearm is repeatedly discharged. The gas pressure control adjustment member 80 also defines an adjustment head portion 90 having a tool engagement receptacle 92 for receiving an adjustment tool, such as a hex or Allen-wrench, star drive wrench, Torx-drive wrench, screw driver or any other similar tool that is typically employed to tighten or loosen screws.

(22) At its inner end the gas pressure control adjustment member 80 has a gas interrupting projection 94 that is located at least partially within the angulated section 87 of the gas supply passage 84 and serves to interrupt the unrestricted propagation of propellant gas within the inclined or angulated portion 84 of the propellant gas passage 86. It should be noted that the gas interrupting projection 94 does not achieve complete shut-off within the gas passage, but rather simply alters the characteristics of pressure and flow as desired by the user of the firearm. The gas interrupting projection 94 is laterally offset with respect to a circular inclined end surface 96 and defines a generally planar gas deflection surface 98 that can be selectively oriented within the gas passage section 84 by rotating the gas pressure control adjustment member 80 with an adjustment tool.

(23) The gas pressure control adjustment member 80 has adjustment surfaces of various geometry, thus permitting a wide range of selective control features. The generally planar gas deflection surface 98 has a rather sharp intersection 100 with a curved or arcuate surface 102. The curved or arcuate surface 102 has a rather broad or smoothly contoured intersection 103 with the generally planar gas deflection surface 98. The gas pressure control adjustment member 80 defines a generally planar end surface 104 and has a curved tapered surface 106 that intersects the planar gas deflection surface 98 and the curved or arcuate surface 102. Since the gas pressure control adjustment member 80 has 360 of rotational adjustment by virtue of its threaded engagement within the internally threaded receptacle 82 the various surfaces and edges of the gas pressure control adjustment member 80 can be adjusted to a variety of different control positions to achieve desired timing control of the bolt carrier and bolt group of the firearm. These control positions may be accurately preset or confirmed by alignment of position adjustment indicia lines or marks 108 on the adjustment head 90 with a reference line or mark 110 on an external angulated surface 85 of the gas key member. Moreover, when the gas pressure or flow and its timing are changed, such as when a suppressor or other rifle component is employed or when the ammunition is changed, the gas pressure control adjustment member 80 can be selectively positioned to compensate for these changes and facilitate proper and efficient gas energized firearm auto-cycling.

(24) In view of the foregoing 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 disclosed herein.

(25) 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.