Fire Control Group

This application is a Continuation of U.S. patent application Ser. No. 17/094,373 filed on Nov. 10, 2020, entitled “FIRE CONTROL GROUP,” which is a Continuation of U.S. patent application Ser. No. 16/655,145 filed on Oct. 16, 2019 now issued as U.S. Pat. No. 10,871,340, entitled “FIRE CONTROL GROUP,” which claims the benefit of U.S. Provisional Patent Application No. 62/746,879 filed on Oct. 17, 2018, entitled “BFSIII™ for AK,” which are hereby incorporated by reference in their entirety for all that is taught and disclosed therein.

The present invention relates to firearms and, more particularly, to a fire control group compatible with firearm systems having widely varying tolerances.

There are many ways to secure a fire control group, or a cartridge fire control group, to a firearm. The AR-15, AK-47, and many other modern firearms generally connect the fire control group to the firearm via a hammer pin, a trigger pin, and a safety selector shaft. While the AR-15 traditionally is manufactured to rather consistent and relatively tight tolerances, the AK-47 has historically been manufactured in many different countries that do not follow consistent specifications and tolerances. In fact, the AK-47 is a design that commonly credits its reliability to the lack of tight tolerances. Consequently, it is rather difficult to manufacture a tight tolerance fire control group that will work in most AK-47s that have been manufactured and distributed through commercial and other channels across the world. Consequently, even though the tolerances of the AK-47 platform vary wildly, a need exists for a tight tolerance trigger system that will safely function in the variety of AK-47 type firearms currently found in the marketplace. In the context of the specification, the term “AK-47” is used broadly to refer to numerous rifles produced on the Kalashnikov platform, including the SKS, AK-74, and others.

Therefore, a need exists for a new and improved fire control group that is compatible with firearm systems having widely varying tolerances. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the fire control group according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of providing a fire control group that is compatible with firearm systems having widely varying tolerances.

The present invention provides an improved fire control group, and overcomes the above-mentioned disadvantages and drawbacks of the prior art. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide an improved fire control group that has all the advantages of the prior art mentioned above.

To attain this, the preferred embodiment of the present invention essentially comprises a receiver having opposed sidewalls defining a space configured to receive a fire control group, the opposed sidewalls each defining a pivot pin aperture, the pivot pin apertures being registered with each other, a fire control group including a trigger received in the space, the fire control group defining a transverse pivot pin passage configured to be registered with the pivot pin apertures of the receiver, the fire control group including a pivoting operational element, the fire control group including a pivot pin supporting the pivoting operational element and received in the pivot pin passage and the pivot pin apertures, the firearm having a hand grip aft of the trigger and defining a screw aperture, and a grip screw engaging the hand grip and engaging the fire control group. The grip screw may occupy a medial plane of the firearm. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached.

There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.

The same reference numerals refer to the same parts throughout the various figures.

An embodiment of the fire control group of the present invention is shown and generally designated by the reference numeral.

illustrates an AK-47 riflewith the improved fire control groupof the present invention installed therein.

illustrates the improved fire control groupof the present invention. More particularly, the fire control group has a fire control cartridgethat maintains tight tolerances between the hammer, trigger, disconnector, and intermittent disconnector spacer. The fire control cartridge uses the existing hammer pinin the firearm receiveras the forward anchor point for the frontof the fire control cartridge. Because the spacing between the hammer pin holesand the trigger pin holesin the left and right sidewalls,of the firearm receiver can be highly variable between AK-47 variants, the trigger pindeliberately does not extend laterally beyond the fire control cartridge to engage the trigger pin holes. The sole purpose of the trigger pin is to secure the trigger to the fire control cartridge. The rearof the fire control cartridge is held in place by the grip screw, which engages threaded aperturedefined by the rear of the fire control cartridge.

There are multiple advantages to not using the trigger pinto secure the fire control cartridgeto the firearm receiver. First, the trigger pin can be precisely positioned relative to the hammer pinbecause the position of the trigger pin is not constrained by the location of the trigger pin holesin the firearm receiver relative to the hammer pin holes. The fire control groupwill still function safely even if the trigger pin holes were inaccurately positioned relative to the hammer pin holes by the firearm receiver's manufacturer. Furthermore, even if the hammer pin holes in the receiver, which serve as the forward anchor point of the fire control cartridge, are slightly mislocated, the decoupling of the trigger pin position from the trigger pin holes is more likely to compensate for the error in the manufacturing of the receiver. This is a critical consideration that enables the fire control groupto function properly in a variety of AK-47 variants having widely different tolerances.

A second advantage to not using the trigger pinto secure the fire control cartridgeto the firearm receiveris that the elevation of the rearof the fire control cartridge can be precisely controlled and firmly established in a selected position. This is accomplished by an adjustable set screwthat received in threaded aperture, traverses vertically through the fire control cartridge, and pushes down on the floorof the firearm receiver. The set screw works against the grip screwto compress a portionof the floor of the firearm receiver between them to firmly set the rear of the fire control cartridge in place. Additionally, the set screw and grip screw can be adjusted to enable the fire control cartridge to ride higher or lower within a channeldefined by the left and right sidewalls,of the firearm receiver depending on the needs of the specific installation. This height adjustment capability is important because the bolt carrier (not shown) height relative to the fire control cartridge can create malfunctions of the AK-47 rifleif the fire control cartridge is not positioned correctly. Furthermore, the set screw and the grip screw can be adjusted to compensate for inconsistent positioning of the safety selector holesin the firearm receiver by various AK-47 manufacturers. In order to function safely, the safety selector shaftmust protrude through the left and right sides of the firearm receiver with plenty of tolerance around the safety selector shaft. The set screw and the grip screw can be adjusted to change the height of the safety selector shaft to compensate for possible deficiencies in the location of the safety selector holes in the firearm receiver.

A third advantage to not using the trigger pinto secure the fire control cartridgeto the firearm receiveris that the grip screwforcibly centers the fire control cartridge within the channelof the firearm receiver. This centering action eliminates the need for other potentially costly or difficult to install spacers that would otherwise be necessary to locate the fire control groupwithin the non-uniform channel of the firearm receiver.

In the current embodiment, the hammer pinhas a length of 1.420 inch to engage the hammer pin holes. The hammer pin is preferably the Original Equipment Manufacturer (OEM) hammer pin included with the AK-47. The trigger pinhas a length of 0.875 inch to ensure the trigger pin does not engage the trigger pin holes. Instead, the trigger pin holesare plugged by left and right plugs,having flanged heads,located within the channelof the firearm receiver to prevent the trigger pin from laterally walking out of the fire control cartridge. The left and right plugs also include inner faces,spaced apart from inner surfaces,of the left and right sidewalls,to establish a lateral positional limit for the fire control group. The grip screwcan be used to secure the conventional hand gripshown, or can be shortened for use with an alternative style of hand grip that has its bottom portion hollowed out.

In the current embodiment, the left and right sidewalls,of the firearmare opposed sidewalls defining a space (channel) configured to receive the fire control group. The hammer pin holesdefined by the opposed sidewalls are pivot pin apertures that are registered with each other. The fire control group includes a triggerreceived in the space. The fire control group defines a transverse pivot pin passageconfigured to be registered with the pivot pin apertures of the firearm receiver. The fire control group includes a pivoting operational element (hammer). The fire control group includes a pivot pin (hammer pin) supporting the pivoting operational element and received in the transverse pivot pin passage and the pivot pin apertures. The firearm has a hand gripaft of the trigger and defining a screw aperture (threaded aperture). The grip screwengages the hand grip and engages the fire control group.

In the current embodiment, the grip screwoccupies a medial planeof the firearm. The grip screwdefines a screw axisperpendicular to the pivot pin (hammer pin). In the current embodiment, the screw axis extends downward and rearward at an angle of 18° relative to vertical. However, it should be appreciated that AK-47s do not have a firmly established standard grip angle. The grip angle varies from rifle to rifle and can exceed ±5° relative to 18° relative to vertical. Because the grip screw angle is relative to the housing that defines “vertical,” and the height of the housing depends upon the housing's rotation about the hammer pin axis, the grip screw angle is variable relative to vertical based on the installation. The variation can be up to +1.5° clockwise (when viewed from the ejection port-side of the rifle) and up to −1° counterclockwise in a US-specification AK-47 receiver that is within tolerance. Because many AK-47 specifications can be in or out of tolerance, up to a 2.5° variational installation range can exist when measured across multiple AK-47 rifle samples. The fire control groupdefines a threaded aperturereceiving the grip screw. The firearm control group includes an adjustable downwardly extending set screwconfigured to establish an elevation of at least a portion of the fire control group. The set screw is adjacent to the grip screw. The set screw is spaced apart from the pivot pin. The fire control group defines a trigger pivot passagereceiving a trigger pinand the triggeris supported by the trigger pin, and therein the trigger pin has a limited length that does not engage the firearm receiver. The firearm receiver defines a trigger pin aperture/holethat is independently located with respect to the trigger pin. The trigger pin ends,are flush with the fire control group. The trigger pin is received between the opposed sidewalls of the firearm receiver. The pivot pin (hammer pin) supporting the pivoting operational element (hammer) is longer than the trigger pin. The hand grip defines a primary grip axis, and the grip screw is perpendicular to the primary grip axis. A portionof the firearm receiver is compressively received between the hand grip and the fire control group.

The fire control groupcan be viewed as a trigger module. The fire control cartridgeis a module housing having module sidewalls,with opposed parallel external wall surfaces,defining a module width. The hammer pinextends transversely through the module sidewalls and has a length greater than the module width such that the hammer pin ends,are configured to be received in opposed pin apertures (hammer pin holes) of the firearm receiver. The module housing defines a threaded apertureat a rear portionof the module housing. The threaded aperture is oriented to receive the grip screwreceived by and engaging hand gripto secure the rear portion of the module housing.

In the context of the specification, the terms “rear” and “rearward,” and “front” and “forward,” have the following definitions: “rear” or “rearward” means in the direction away from the muzzle of the firearm while “front” or “forward” means it is in the direction towards the muzzle of the firearm.

While a current embodiment of a fire control group has been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.