Apparatus and method for preventing the bolt carrier of a firearm from moving forward after firing the last round of ammunition, and signaling when the firearm has run out of ammunition.
The invention is designed to be fitted into the AK47-type semiautomatic firearms to provide a missing but vital feature of locking the reciprocating bolt assembly of said firearm after having chambered, fired and ejected the last cartridge from its removable magazine. The invention is designed to be installed into the receiver portion of the firearm as well as incorporating a modification into the removable magazine housing and follower. The invention consists of a number of components that will work in cooperation with each other to provide the above desired feature.
The AK47-type firearms have a number of weaknesses. On of these is the lack of a bolt stop or bolt catch feature that prevents the bolt and the bolt carrier assembly from moving forward to battery upon firing and ejecting the last round from the ammunition feeding device or magazine. This shortcoming often leads to the users unanticipated running out of ammunition unless the user counts the number of bullets fired from the magazine. In most cases, this results in a dry fire, where the trigger is pulled on an empty chamber. This slows down the operators response time to refresh the firearms magazine.
The unmodified rifle and its operation is fully described in a publication entitled The AK-47 Assault Rifle edited by Wyant La Mont (Normount Technical Publications, Wickenburg, Ariz., Copyright 1969 by Donald B. Mclean). This type of rifle is also described in the World patent NO. WO9905467. Therefore, its operation will not be described in detail here.
What is needed is a mechanism that can easily be added on a (AK47-type) firearm, which prevents the bolt carrier from moving forward upon firing/ejecting of the last round of ammunition and which provides a signal to the user to warn him/her that he/she has run out of ammunition.
SUMMARY OF INVENTIONAlthough this invention is described in conjunction with AK47-type firearms, other types of firearms may benefit from the present invention, and are not meant to be excluded from the scope of the present invention. AK47-type firearms include, but are not limited to, the AKM, MAK-90, MAADI and Krinkov series firearms. These firearms commonly have a stamped steel (or machined steel) receiver body, a removable single (or double) stack stamped steel (or molded plastic box magazine) with stamped steel (or molded plastic) magazine follower, and semi-automatic (or automatic) rate fire capability.
A mechanism in accordance with this invention automatically locks the bolt carrier in the semi-rearward position after having chambered, fired and ejected the last round from the magazine. This invention also allows the user to manually lock the bolt carrier in the semi-rearward position by use of a thumb release, and manually release the locked bolt carrier from the semi-rearward position to battery by the thumb release, with or without an empty or charged magazine installed in the receiver. Further, upon having locked the bolt carrier semi-rearward by the use of this invention, it also allows the magazine to be removed and replaced without releasing the bolt carrier. Furthermore, this invention allows the release of the bolt carrier when a fully charged magazine is installed, by pulling on the charging handle of the bolt carrier rearward until the bolt catch (or bolt stop) is disengaged. This allows the bolt carrier to move forward to battery, stripping a bullet from the magazine and chambering it. Also, this invention allows the manual release of the bolt carrier either with the thumb release or the bolt carrier charging handle when there is no magazine installed, allowing the bolt carrier to move forward to battery.
The invention, therefore, provides a visual indication of the last cartridge fired by keeping the bolt carrier in the open or semi-rearward position, provides for quicker removal of empty magazine and installation of a fresh magazine, and allows quicker charging of the firearm by the use of an external thumb release.
BRIEF DESCRIPTION OF DRAWINGS
Referring to
In a preferred embodiment, the invention is comprised of six major components as shown in
The sensor lever 19 with integral sensor tab 31, integral thumb release 32 protruding through the bottom of the receiver 1 in the area of the magazine well 27, pivotally mounted on a pin 21. The pin 21 is securely fastened to the inside left wall 2 of the receiver 3. The bolt catch lever 22 is pivotally mounted on the solid rivet 9, connecting the walls 2, 3 of the firearm. A catch return spring 8 which imparts a continuous counterclockwise torque (when viewed in
Upon imparting a clockwise rotation (when viewed in figures 3, 4, 5) on the sensor lever 19, rotating about pin 21, lever 19 engages the catch lever 22 through the interaction of the hole 16 in the sensor lever 19 and the corresponding pin 14 in the catch lever 22. This interaction results in the counter clockwise rotation of the catch lever 22, about the receiver rivet 9, on which it is mounted. In this condition the catch lever 22 is ready to engage the carrier 13.
The sensor lever 19 further engages the catch lever 22 through the interaction of a second hole 17 and a corresponding pin 15 in the catch lever 22. However, this set of hole 17 and pin 15 only engage each other when a counter clockwise rotation (when viewed in
The description of operation will assume that a charged magazine has been installed into the firearm. After having fired and ejected the second to last cartridge, the carrier 13 moves forward under the action of the return spring 29 to chamber the last cartridge, at which point the magazine follower tab 26 also protrudes up through the magazine housing 5 by means of slot 34, imparting a clockwise rotation (when viewed in
As the magazine spring (not shown) is compressed under the installation of cartridges within the magazine housing 5, the magazine follower 4 and tab 26 attached thereon, are retracted into the housing 5. Upon installing a fully charged magazine into the firearms magazine well 27, the magazine follower tab 26 no longer impinges on the sensor lever 19. The absence of the magazine follower tab 26 allows for the return spring 8 to tend to impart a clockwise rotation (when viewed in
Upon having removed the empty magazine, or having installed a fully charged magazine, the magazine follower tab 26 no longer impinges on the sensor lever 19. The absence of the magazine follower tab 26 allows for the catch lever 22 return spring 8 to tend to impart a clockwise rotation (when viewed in
Claims
1. In a firearm, a mechanism for preventing a bolt carrier of the firearm from moving forward after having fired the last round of ammunition, and thereby providing a signal to indicate an empty condition of a magazine, the mechanism comprising:
- a) a sensor lever pivotally connected to a receiver of said firearm;
- b) a thumb release integral to the sensor lever;
- c) a catch lever connected to the receiver of said firearm by use of a pivot pin;
- d) a return spring removably attached to said catch lever;
- e) a box magazine modified by a slot located at the top of the magazine opening; and
- f) a tab permanently mounted on a magazine follower and protruding through said slot in the magazine housing.
2. The mechanism of claim 1, wherein the firearm is an AK47-type or its variant.
3. A method of preventing a bolt carrier of a firearm from moving forward after having fired the last round of ammunition, the method comprising the steps of:
- a) sensing the absence of a cartridge in a magazine by the interaction of a tab on a magazine follower and a sensor lever pivotally mounted on a receiver of a firearm;
- b) actuating by the sensor lever of a catch lever pivotally mounted on the receiver of said firearm; and
- c) interrupting the forward motion of a the bolt carrier by a catch lever.
4. The method of claim 3, wherein the firearm is an AK47-type or its variant.
Type: Application
Filed: Mar 21, 2004
Publication Date: Jan 6, 2005
Inventor: Peter Kiss (Santa Clarita, CA)
Application Number: 10/708,731