US20170328662A1

US20170328662A1 - Firearm pin retainer plate and pivot pins

Info

Publication number: US20170328662A1
Application number: US15/593,365
Authority: US
Inventors: Christian Kager Welch; Daniel Earl Fisher; Nicholas Adam Rode
Original assignee: Kns Precision Inc
Current assignee: Kns Precision Inc
Priority date: 2016-05-16
Filing date: 2017-05-12
Publication date: 2017-11-16

Abstract

Firearm pin retainer plates and pins have a frame defining an internal space, a moving action part defining a bore and connected to the frame within the space, a pivot pin connected to the frame and to the action part such that the action part pivots with respect to the frame, the pivot pin having a cylindrical body portion closely received in the bore and defining a pin axis, the pivot pin having a first flat surface portion, a retention element connected to the frame within the space and having a first retention facility adapted to engage the first flat surface portion to prevent rotation of the pin with respect to the frame. The pin may have a second flat surface portion opposed to the first flat surface portion. The first retention facility may define a slot having opposed edges operable to engage the first and second flat surface portions.

Description

This application claims the benefit of U.S. Provisional Patent Application No. 62/336,817 filed on May 16, 2016, entitled “NON-ROTATIONAL HAMMER/TRIGGERPIN KIT FOR AK47 AND VARIANTS,” which is hereby incorporated by reference in its entirety for all that is taught and disclosed therein.

FIELD OF THE INVENTION

The present invention relates to firearms, and more particularly to a pin retainer plate and pins that prevents the pins from rotating with respect to the receiver.

BACKGROUND OF THE INVENTION

The AK-47 is the most popular and widely used assault rifle in the world. It is well known for its reliability under harsh service conditions, ease of use, and low production cost. The conventional design uses a retainer spring in the form of a bent elongate wire to hold the hammer and trigger pins in the receiver. While the retainer spring is generally reliable, the retainer spring does not prevent the hammer and trigger pins from rotating, eventually leading to undesirable wear on the receiver pin axis holes that results in a loose fit. Furthermore, if the retainer spring does fail, the rifle becomes inoperable until the retainer spring is replaced, and trigger group parts are vulnerable to being lost.
A variety of retainer plates have been developed to replace the retainer spring with a stronger part that is less vulnerable to failure. Furthermore, retainer plates make reassembly of the trigger group easier compared to using the conventional retainer spring. Unfortunately, existing retainer plates do not prevent the hammer and trigger pins from rotating. In addition, existing retainer plates require the safety selector to be removed prior to installing the retainer plate, and some require the hammer and trigger with their respective pins to be installed before the retainer plate and safety selector are installed. Because some semi-automatic and all fully automatic AK-47 rifles require the safety selector to be installed before the trigger and hammer with their respective pins, many existing retainer plates are not compatible.
Existing products are used to provide an anti-rotation function for pins on firearms with external surfaces. These include the Gen 2 Non-Rotating Trigger/Hammer Pins provided by KNS Precision Inc. of Fredericksburg, Tex. These are used for AR-15 rifles and use pins that have ends formed with a blade having flat surfaces analogous to the tip of a flat blade screwdriver. An external retainer bar having a mating slotted cap (analogous to a slotted screw head) on one end to engage the blade prevents rotation of the bladed pin, and the retainer bar is secured at its opposite end with a fastener to a tapped hole in the end of another pin. While effective for the AR-15 and similar designs with no operating or mounting components on the exterior surfaces of the lower receiver where these anti-rotate components are connected, they are unsuitable for other applications such as the AK-47 and its variants. These typically require optics mounts to be mounted to the left face of the receiver, and have a safety selector lever on the right side, preventing the external mounting of anti-rotation components. Because the existing Non-Rotating Trigger/Hammer Pins have the flat blade section at the end so they can be engaged by the slotted cap, and the slotted cap is attached by external fasteners, this is not suitable for the AK-47.
Therefore, a need exists for a new and improved firearm pin retainer plate and pivot pins that prevents the pins from rotating with respect to the receiver and can be installed with the safety selector already in place. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the firearm pin retainer plate and pivot pins 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 pin retainer plate with pins that prevents the pins from rotating with respect to the receiver and can be installed with the safety selector already in place.

SUMMARY OF THE INVENTION

The present invention provides an improved firearm pin retainer plate and pivot pins, 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 firearm pin retainer plate and pivot pins 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 defining an internal space, a moving action part defining a bore and connected to the frame within the space, a pivot pin connected to the frame and to the action part such that the action part pivots with respect to the frame, the pivot pin having a cylindrical body portion closely received in the bore and defining a pin axis, the pivot pin having a first flat surface portion, a retention element connected to the frame within the space and having a first retention facility adapted to engage the first flat surface portion to prevent rotation of the pin with respect to the frame. The pin may have a second flat surface portion opposed to the first flat surface portion and the first retention facility may define a slot having opposed edges operable to engage the first and second flat surface portions. The opposed flat surface portions may be parallel to each other. 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.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the current embodiment of a firearm pin retainer plate and pivot pins constructed in accordance with the principles of the present invention installed in a rifle.

FIG. 1A is an enlarged view of circle 1A of FIG. 1.

FIG. 2 is a front isometric view of the current embodiment of the firearm pin retainer plate and pivot pins of FIG. 1 showing the relationship with an installed safety selector.

FIG. 3 is a left side view of the current embodiment of the firearm pin retainer plate of FIG. 1.

FIG. 4 is an isometric view of the current embodiment of the pin of FIG. 1.

FIG. 5 is a top isometric view of the current embodiment of the firearm pin retainer plate and pivot pins of FIG. 1 installed in a receiver.

FIG. 6 is a side enlarged view of the current embodiment of the firearm pin retainer plate of FIG. 1 showing how the rear fork snaps over the safety selector pin to install the firearm pin retainer plate.

FIG. 7 is an isometric view of the current embodiment of the pins of FIG. 1 installed in a receiver showing how the heads of the pins are accessible from outside of the receiver.

FIG. 8 is a rear sectional fragmentary view of the current embodiment of the firearm pin retainer plate and pivot pins of FIG. 1 installed in a receiver.

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

DESCRIPTION OF THE CURRENT EMBODIMENT

An embodiment of the firearm pin retainer plate and pivot pins of the present invention is shown and generally designated by the reference numeral 10.
FIGS. 1-4 illustrate the improved firearm pin retainer plate and pivot pins 10 of the present invention. More particularly, the firearm pin retainer plate and pivot pins are shown installed in the receiver 100 of a rifle 114 in FIGS. 1 and 1A, which is an AK-47 in the current embodiment. A portion of the left sidewall 102 of the receiver is cutaway to expose the firearm pin retainer plate and pivot pins. The relationship between an installed safety selector 104 having a selector pin 106 and the firearm pin retainer plate and pivot pins is shown in FIG. 2. FIG. 3 shows the pin retainer plate 12 by itself, and FIG. 4 shows a pivot pin 60 by itself. The pin retainer plate has a front 14, rear 16, right side 18, left side 20, top 22, and bottom 24. The pin retainer plate is a retention element that is a flat planar member. The front of the pin retainer plate has a front fork 26 that defines a slot 28 with opposed flat sides 30 that serves as a first retention facility. The bottom of the pin retainer plate has a bottom fork 32 that defines a slot 34 with opposed flat sides 36 that serves as a second retention facility. The bottom fork slot is spaced apart from the front fork slot. The opposed flat sides of the front fork slot are parallel to a first axis 86, and the opposed flat sides of the bottom fork slot are parallel to a different second axis 88 angularly offset from the first axis. Thus, the front fork slot is open in a direction away from the bottom fork slot. The bottom fork slot is open in a direction lateral to a line connecting the front fork slot and the bottom fork slot. The left side of the pin retainer plate includes an outwardly protruding dimple 82.
A vertical tab 38 having a front 40, rear 42, right side 44, left side 46, top 48, and bottom 50 is attached by the bottom left side to the rear 16 of the pin retainer plate 12. A rear fork 52 is attached to the top left side of the vertical tab. The rear fork defines a curved slot 54 that extends between an elongated top tooth 56 and a truncated bottom tooth 58. When the pin retainer plate is installed, the selector pin 106 is received within the curved slot in the rear fork.
The two pivot pins 60 shown enlarged in FIG. 2 are identical. Each pivot pin has a head 62, and an enlarged diameter end portion/retention portion 64 that includes a second cylindrical portion adapted to be received in an aperture defined by the receiver 100, tapered portion 66, a first smooth cylindrical body portion 68, end 70, and a pivot pin axis 84 defined by the cylindrical body portion. The head defines a tool interface, which is a slot 72 for a flat head screwdriver in the current embodiment, but can be any suitable tool interface including Phillips, hexagonal, and hexalobular internal. The forward pivot pin pivotally bears a hammer 116 (shown in FIGS. 1 and 1A), which is a moving action part defining a bore 118 that closely receives the smooth cylindrical body portion. The rearward pivot pin pivotally bears a trigger 120, which is a moving action part defining a bore (not visible) that closely receives the smooth cylindrical body portion. The enlarged diameter end portion of each pivot pin defines a first slot pair 74 having a first flat surface portion and a second flat surface portion (flats 76) with the second flat surface portion opposed and parallel to the first flat surface portion and spaced apart from the first flat portion by a spacing greater than a diameter of the cylindrical body portion. The enlarged diameter end portion of each pivot pin also defines a second slot pair 78 having a third flat surface portion and a fourth flat surface portion (flats 80) with the fourth flat surface portion opposed and parallel to the third flat surface portion and spaced apart from the third flat portion by a spacing greater than a diameter of the cylindrical body portion. The slot pairs are perpendicular to the pivot pin axis and are rotationally offset 90° from each other, with the first slot pair being located closer to the head than the second slot pair such that the second slot pair is linearly offset along the length of the pivot pin from the first slot pair. The first flat surface portion is non-concentric with the pivot pin axis 84 such that the pin is prevented from rotating about the pin axis with respect to the frame. The retention portion that defines the flat surface portions is positioned between the first and second cylindrical portions.
FIGS. 5 and 8 illustrate the improved firearm pin retainer plate and pivot pins 10 of the present invention. More particularly, the firearm pin retainer plate and pivot pins are shown installed in the frame/receiver 100 of the rifle 114. The receiver has a left side wall 102, which has a planar portion, and a right side wall 108, which define an internal space between them that receives the hammer 116 and trigger 120. The firearm pin retainer plate 12 has a flat body portion overlaying the planar portion of the left side wall of the receiver. Because so many variations of the AK-47 rifle have been constructed, the side wall of the receiver can have a thickness ranging from 0.035 inch to 0.081 inch. The dimple 82 (not visible) provides an interference fit by pushing the pin retainer plate 12 inward away from the side wall. As a result, the pins 60 are effectively pulled into the receiver by the pin retainer plate. The front fork slot 28 and bottom fork slot 34 engage a selected slot pair 74 or 78 on each pin depending upon the receiver side wall thickness.
For a receiver having a side wall thickness in the lower or narrower half of the range, the fork slots engage the first slot pair 74 that is closest to the head 62 of the pivot pin. For a receiver having a side wall thickness and the upper or wider half of the range, the fork slots engage the second slot pair 78 that is furthest from the head of the pivot pin. The engagement of the flat sides 30, 36 of the fork slots with the flats 76 or 80 of the pivot pins acts like a wrench and prevents the pins from rotating with respect to the receiver. The fork slots' engagement with two pins with the fork slots being angularly offset also prevents the pin retainer plate from rotating with respect to the receiver. As a result, the only rotational motion is between the hammer, trigger, and their respective pivot pins, which prevents wear on the receiver pin axis apertures 110, 112 in the right side wall of the receiver that receive the smooth cylindrical body portions of the pivot pins and the pin axis apertures in the left side wall of the receiver (not visible).
FIG. 6 illustrates the firearm pin retainer plate 12 of the present invention. More particularly, the pin retainer plate is shown in the process of being installed in the receiver 100. The vertical tab 38 serves as a leaf spring and enables the truncated bottom tooth 58, which is a resilient latch portion, to snap over and releasably engage a fixed element on the frame/receiver, which is the safety selector pin 106 of the installed safety selector 104. The pin retainer plate is an elongated member, and the resilient latch portion is on an end of the retention element opposite the first retention facility (the front fork slot 28). As a result, the safety selector can be installed first, followed by the two pins 60 with the trigger 120 and hammer 116 as required by some semi-automatic and all fully automatic variants of the AK-47 rifle. Subsequently, the tool interface 72 on the head 62 of the forward pin is used to orient a selected slot pair 74 or 78 to be received within the front fork slot 28. Then, the tool interface 72 on the head 62 of the rearward pin is used to orient a selected slot pair 74 or 78 to be received within the bottom fork slot 34. Finally, the rear fork slot 54 is snapped over the safety selector pin as previously described to secure the pin retainer plate within the receiver.
FIG. 7 illustrates the left side wall 102 of the receiver 100 of the present invention. More particularly, the head 62 of each pivot pin 60 protrudes from the left side wall of the receiver through pin axis apertures (not visible), which permits the tool interface 72 to be accessed from outside the receiver. Thus, the orientation of each pivot pin can be controlled to orient a selected slot pair 74, 78 of the pivot pins with the flat sides 30, 36 of the front fork slot 28 and bottom fork slot 34 during installation of the firearm pin retainer plate 12.
In the current embodiment, the firearm pin retainer plate has a thickness of 0.032 inch. The first slot pair is 0.055 inch from the head. The second slot pair is 0.080 inch from the head. The top tooth of the rear fork has a length of 0.480 inch, the bottom tooth of the rear fork has a length of 0.265 inch and the rear fork tooth has a radius of 1.100 inch.
While a current embodiment of a firearm pin retainer plate and pivot pins 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. For example, the slot pairs on the pins could instead be a single flat or non-cylindrical surface, and the opposite sides of the fork flats that serve as a wrench element could engage the flat and an opposite point on the cylindrical surface.
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

I claim:

1. A firearm comprising:

a frame defining an internal space;

a moving action part defining a bore and connected to the frame within the space;

a pivot pin connected to the frame and to the action part such that the action part pivots with respect to the frame;

the pivot pin having a cylindrical body portion closely received in the bore and defining a pin axis;

the pivot pin having a first flat surface portion; and

a retention element connected to the frame within the space and having a first retention facility adapted to engage the first flat surface portion to prevent rotation of the pin with respect to the frame.

2. The firearm of claim 1 wherein the pin has a second flat surface portion opposed to the first flat surface portion and the first retention facility defines a slot having opposed edges operable to engage the first and second flat surface portions.

3. The firearm of claim 2 wherein the opposed flat surface portions are parallel to each other.

4. The firearm of claim 3 wherein the opposed flat surface portions are perpendicular to the pin axis.

5. The firearm of claim 1 wherein the retention element is a flat planar member.

6. The firearm of claim 1 wherein the retention element has a second retention facility spaced apart from the first retention facility and adapted to engage a second pin to prevent rotation of the retention facility with respect to the frame.

7. The firearm of claim 6 wherein the first retention facility has opposed side edges parallel to a first axis, and the second retention facility has opposed side edges parallel to a different second axis angularly offset from the first axis.

8. The firearm of claim 6 wherein the first retention facility has a slot open in a direction away from the second retention facility

9. The firearm of claim 8 wherein the second retention facility has a slot open in a direction lateral to a line connecting the first retention facility and second retention facility.

10. The firearm of claim 1 wherein the frame includes a planar portion and the retention facility has a flat body portion overlaying the planar portion of the frame.

11. The firearm of claim 1 wherein the retention facility has a resilient latch portion adapted to releasable engage a fixed element on the frame.

12. The firearm of claim 11 wherein retention element is an elongated member, and the resilient latch portion is on an end of the retention element opposite the first retention facility.

13. The firearm of claim 1 wherein the pivot pin has an enlarged end portion adjacent to the cylindrical body portion and defining the first flat surface portion.

14. The firearm of claim 13 wherein the enlarged end portion defines a second flat surface portion spaced apart from the first flat surface portion by a spacing greater than a diameter of the cylindrical body portion.

15. The firearm of claim 2 including third and fourth flat surface portion spaced apart from each other, rotationally offset from the first and second flat surface portions, and linearly offset along the length of the pivot pin from the first and second flat surface portions.

16. A pivot pin for a firearm having a frame comprising:

a first elongated cylindrical portion adapted to receive a pivoting firearm part;

the elongated cylindrical portion defining a pin axis;

the pin having a first retention portion adjacent to the elongated cylindrical portion;

the retention portion having a first surface portion adapted for engagement by a retention element connected to the frame;

the first surface portion being non-concentric with the pin axis such that the pin is prevented from rotating about the pin axis with respect to the frame;

the pin having a second cylindrical portion adapted to be received in an aperture defined by the frame; and

the first retention portion being positioned between the first and second cylindrical portions.

17. The pivot pin of claim 16 wherein the first surface portion is a flat surface.

18. The pivot pin of claim 16 wherein the pivot pin has an enlarged end portion adjacent to the second cylindrical portion.

19. The pivot pin of claim 16 including a second retention portion between the first and second cylindrical portions, the second retention portion having a second surface portion being non-concentric with the pin axis, the second retention portion having a different location along the length of the pin from the first retention portion.

20. The pivot pin of claim 19 wherein the second surface portion is angularly offset from the first surface portion.