LIGHTWEIGHT MACHINE GUN RECEIVER AND METHOD OF MANUFACTURING
A lightweight machine gun receiver has a frame having opposed left and right shell portions configured to separably connect to each other in a connected condition, when in the connected condition, the frame defining an internal space configured to receive a reciprocating bolt, have a barrel connection facility, and have a trigger connection facility, when in the connected condition, the frame being an elongated body having a left side panel having upper and lower edges and an opposed right side panel having upper and lower edges, each of the left and right shell portions having top and bottom spans extending laterally from the associated side panel toward corresponding opposed top and bottom spans, the top and bottom spans having respective free ends having respective top and bottom span mating facilities configured to mate with each other, and the top and bottom span mating facilities each having a sliding interface.
This application is a Continuation of U.S. patent application Ser. No. 17/106,299 filed on Nov. 30, 2020, entitled “LIGHTWEIGHT MACHINE GUN RECEIVER AND METHOD OF MANUFACTURING,” which claims the benefit of U.S. Provisional Patent Application No. 62/948,930 filed on Dec. 17, 2019, entitled “LIGHTWEIGHT MACHINE GUN RECEIVER BOX AND METHOD OF MANUFACTURING,” which are hereby incorporated by reference in their entirety for all that is taught and disclosed therein.
FIELD OF THE INVENTIONThe present invention relates to firearms, and more particularly to a lightweight machine gun receiver that joins opposed shell portions using dovetail joints to eliminate connecting bolts and welding to reduce weight.
BACKGROUND OF THE INVENTIONBelt-fed machine guns have been in use around the world for many years. The M2, M240, and M1919 machine guns, general-purpose machine guns of choice for large standing armies, were constructed from conventional materials such as carbon steel, riveted together using primitive and laborious manufacturing methods. For example, the M240 machine gun's receiver/frame had over 75 individual parts, riveted together by hand. Although these machine guns had significant firepower and other advantages relevant to Cold War-era battle situations, these machine guns had the considerable disadvantage of being extremely heavy and quite long, making them difficult to carry by foot soldiers.
A complete discussion of the problems with conventional machine gun construction approaches is disclosed in U.S. Pat. No. 7,937,877 to Barrett, which is incorporated into this application by reference in its entirety. There are also several prior art references cited in the '877 Patent that disclose the construction of firearms, both toy and real guns, having left and right frames, left and right housings, and/or left and right shells. The left shell and the right shell of the '877 Patent are welded together to join them at the medial plane by an elaborate welding process. All of the references cited in the '877 Patent utilize bolts, rivets, and/or welding for joining a left shell to a right shell during the manufacture of guns, including machine guns.
Therefore, a need exists for a new and improved lightweight machine gun receiver that joins opposed shell portions using dovetail joints to eliminate connecting bolts and welding to reduce weight. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the lightweight machine gun receiver 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 joining opposed shell portions using dovetail joints to eliminate connecting bolts and welding to reduce weight.
SUMMARY OF THE INVENTIONThe present invention provides an improved lightweight machine gun receiver, 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 lightweight machine gun receiver that has all the advantages of the prior art mentioned above.
To attain this, the preferred embodiment of the present invention essentially comprises a frame having opposed left and right shell portions, the left and right shell portions configured to separably connect to each other in a connected condition, when in the connected condition, the frame defining an internal space configured to receive a reciprocating bolt, have a barrel connection facility, and have a trigger connection facility, when in the connected condition, the frame being an elongated body having a left side panel having upper and lower edges and an opposed right side panel having upper and lower edges, each of the left and right shell portions having a top span extending laterally from the associated side panel toward a corresponding opposed top span, the top spans having respective free ends having respective top span mating facilities configured to mate with each other, each of the left and right shell portions having a bottom span extending laterally from the associated side panel toward a corresponding opposed bottom span, the bottom spans having respective free ends having respective bottom span mating facilities configured to mate with each other, and the top and bottom span mating facilities each having a sliding interface. 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.
DESCRIPTION OF THE CURRENT EMBODIMENTAn embodiment of the lightweight machine gun receiver of the present invention is shown and generally designated by the reference numeral 10.
The sliding interfaces 90, 92, 94, 96 are operable when connected to prevent relative movement of the left shell portion and the right shell portion except in a single sliding direction. In the current embodiment, the sliding interfaces constrain movement of the opposed left and right shell portions 14, 16 to movement only in a vertical direction with respect to each other. As shown in
It should be appreciated that the opposed left and right shell portions 14, 16 are unitary parts that are interconnectable. The left and right barrel connection facilities 20, 22 each include a threaded portion 118, 120 visible in
By reducing the frame to two parts and fastening them together by dovetail joints, the weight of the resulting lightweight machine gun receiver is greatly reduced compared to conventional approaches employing connecting bolts and welding. The weight is sufficiently reduced that the resulting lightweight machine gun can be safely used by a single individual. Furthermore, not only is the complexity and expense of an elaborate welding process eliminated, but the dovetail joints of the current invention provide a stronger and more rigid connection between the left and right shell portions compared to employing connecting bolts and welding. This makes the frame of the lightweight machine gun receiver more suited to withstand the forces associated with the operation of a belt fed machine gun. Furthermore, the use of single integral sheets of metal that have been precisely machined to produce each of the opposed left and right shell portions reduces the cost and length of the frame compared to conventional approaches to manufacturing a machine gun frame. The interior surfaces of each of the opposed left and right shell portions has a plurality of machined projections at precise locations that, when the left and right shell portions are joined, act as a frame to engage the essential components of a machine gun, including the bolt operating assembly, the trigger assembly, and the barrel assembly. The inside surface of the left shell portion has a similar, but not identical, array of protrusions that function with the operating elements on the right shell inside surface. The inside surface protrusions for left and right shell portions are precision machined for maximum cooperation with the corresponding protruding elements for the essential and proper operation of the machine gun components mounted inside the frame. The frame forms a box capable of receiving all of the necessary essential components of a machine gun, such as a M240 family and MAG58 family of weapons, using existing off-the-shelf components that include the barrel assembly and gas tube attached into the front forward end of the frame. The frame also has a rear vertical section that optionally includes connectors to attach a butt stock plate removably to the frame. The frame is sized and constructed to receive a conventional trigger assembly for a machine gun. The frame includes sized and shaped openings of the proper chamber area to receive mechanisms that provide for the feeding and ejection of ammunition in a high-speed manner.
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 lightweight machine gun receiver 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. Although machine guns have been disclosed, the frame assembled from opposed left and right shell portions and secured by dovetails is also suitable for use with other firearms. Furthermore, any suitable interlocking fit or joint could be used instead of the dovetail joint disclosed. In addition, although the left and right shell portions meeting at a medial vertical plane is disclosed, the left and right shell portions can also meet at a plane offset from vertical to facilitate manufacturing, reduce costs, or for other design reasons. Thus, the sliding direction could be at a variety of angles, including horizontal or rotational, in addition to the vertical sliding direction disclosed. 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.
Claims
1. A firearm comprising:
- a frame having opposed first and second shell portions;
- the first and second shell portions configured to separably connect to each other in a connected condition;
- when in the connected condition, the frame defining an internal space;
- the first and second shell portions having respective mating facilities configured to mate with each other; and
- the mating facilities each having a sliding interface.
2. The firearm of claim 1 wherein the sliding interface is a dovetail joint.
3. The firearm of claim 1 wherein the sliding interface is operable to constrain movement of the left and right shell portions to movement only in a vertical direction with respect to each other.
4. The firearm of claim 1 wherein the frame defines a frame axis and wherein the sliding interface is operable to constrain movement of the left and right shell portions to an interface direction perpendicular to the frame axis.
5. The firearm of claim 1 wherein each of the sliding interfaces includes a junction profile having an articulated shape.
6. The firearm of claim 1 wherein the left and right shell portions meet at a medial vertical plane.
7. The firearm of claim 1 wherein each of the sliding interfaces includes closely mating cylindrical forms defining a sliding axis.
8. The firearm of claim 1 wherein each of the sliding interfaces includes a protrusion on one of the left and right shell portions, and a recess on the other of the left and right shell portions adapted to closely receive the protrusion.
9. A firearm comprising:
- a frame having opposed interconnectable first and second shell portions;
- the first shell portion having a first mounting facility;
- the second shell portion having a second mounting facility; and
- the first mounting facility and the second mounting facility comprising a sliding interface operable when connected to prevent relative movement of the first shell portion and the second shell portion except in a single sliding direction.
10. The firearm of claim 9 wherein the sliding direction is vertical.
11. The firearm of claim 9 wherein the sliding direction is perpendicular to an axis associated with a space defined by the left and right shell portions.
12. The firearm of claim 9 wherein each of the left and right shell portions includes a major planar sidewall and wherein the sliding direction is parallel to the major planar sidewalls.
13. The firearm of claim 15 wherein the left and right planar sidewalls each includes a span extending laterally from the respective left and right planar sidewalls, and the spans each having free ends including the sliding interface.
14. The firearm of claim 9 wherein the left and right shell portions meet at a medial vertical plane.
15. The firearm of claim 9 wherein the sliding interface is a dovetail joint.
16. The firearm of claim 9 wherein the sliding interface is operable to constrain movement of the left and right shells to movement only in a vertical direction with respect to each other.
17. The firearm of claim 9 wherein the sliding interface includes closely mating cylindrical forms defining a sliding axis.
18. The firearm of claim 9 wherein the sliding interface includes a protrusion on one of the left and right shell portions, and a recess on the other of the left and right shell portions adapted to closely receive the protrusion.
Type: Application
Filed: Nov 16, 2021
Publication Date: Aug 4, 2022
Inventor: Travis Tabb (Friendswood, TX)
Application Number: 17/528,090