Patent Application
20100313459
1. Field of Invention
The invention relates in general, to firearms, and more particularly, to a spring loaded firing pin safety catch mechanism designed to prevent the unintentional discharge of a firearm.
2. Prior Art
Numerous firing pin safety devices have been developed and implemented over the years with a varying degree of success. These safety devices have the general purpose of preventing the unintentional discharge of a firearm should the weapon be violently struck from the front (for example, if the firearm accidentally falls on the group causing the muzzle of the weapon to strike a potentially hard surface), or should debris become wedged between the firing pin and its housing causing the firing pin to be stuck in the firing or primed position.
Firing pins of the “floating” variety, which do not have any mechanical means preventing the tip from contacting the primer of a cartridge, are common in both the M16 and AK family of firearms. The M16 and its derivates are arguably the most prolific type of firearm in the United States being used by military, law enforcement and civilian shooters. When a hammer strikes the rear end of the firing pin (“front” is understood throughout this document to mean the direction that a discharged projectile would leave the host firearms barrel and “rear” is understood to be opposite of “front”) its energy is transferred to the firing pin which responds by moving forward through the separation distance and striking the primer of the loaded cartridge being held by the barrel's chamber.
Unfortunately, kinetic energy may also be imparted to a floating firing pin unintentionally such as when a weapon is dropped by the user accidentally. Another possibility, when the action of the firearm is released after being drawn fully to the rear, upon seating the firing pin, due to inertia, is still traveling forward only stopping after it strikes the primer of the loaded cartridge. This often leads to a small dimple of the primer's surface. These provided examples, under the right circumstance, could cause a weapon to accidentally discharge.
Devices such as discussed in U.S. Pat. No. 2,848,832 & U.S. Pat. No. 6,145,234 propose a catch-like safety mechanism mounted to the breech of a firearm. These safety mechanisms rely on a catch which faces the firing pin. The firing pin has a recess proximate its rear end. The recess is located opposite the safety catch or circumferential about the rear end (in the case of U.S. Pat. No. 6,145,234) located opposite the safety catch formed on the safety element. A means to force the safety catch into operational contact with the firing pin recess is provided by both designs. When the safety catch is engaged with the recess, the firing pin is secured and cannot move toward the primer of a cartridge.
In the above mentioned safety elements, the safety element are lengthened rearward by a release part having a camming surface. The camming surface of the release parts extends into the travel path of the hammer directly behind the rear of the firing pin. When the hammer strikes the camming surface, and in so doing, forcing the release part, and thus the safety element to the side such that the firing pin is released by the safety catch just prior to the firing pin being struck by the hammer. This results in the firing pin being able to move under the pressure exerted by the hammer resulting in the firearm discharging a round.
While the above described safety mechanisms are effective, they are not readily adaptable to the M16 family of weapons. Nothing in these prior art examples would create an operative combination. Further, as example, U.S. Pat. No. 6,145,234 incorporates the extractor element into the leaf spring used in conjunction with the safety catch. There is no way to incorporate such a design into the M16 family of weapons due to the rotational separation of the bolt from the bolt carrier during normal operation. Yet, a need to implement a mechanism which prevents the “floating” movement of the firing pin in the M16 family of weapons and those like it persist.
Another weakness with prior art firing pin safeties is that they allow the firing pin a limited range of motion even when held in the rest position. The forward inertia generated when the action is closed coupled with the movement still allowed the firing pin allows the tip of the firing pin to dimple the primer. While it has not been proven that this situation causes out of battery detonation of the loaded cartridge there is evidence that suggest it does. Out of battery detonation occurs when a loaded cartridge is discharged prior to the bolt and cartridge being fully seated in the chamber of the host firearm.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
3. Objects and Advantages
Accordingly several objects and advantages of the present invention are
Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
The herein disclosed invention consists of a firing pin safety catch mechanism designed for use with a firearm having a separate bolt carrier assembly and a trigger mechanism. The trigger mechanism includes a hammer, firing pin, and a firing spring. The hammer is movable from a cocked position through a path of travel to strike the firing pin. The firing pin spring biases the firing pin into a rest position wherein the tip of the firing pin is not protruding through the face of the bolt. The firing pin has a proximal end and a catch surface, or recess, adjacent the proximal end. The firing pin safety catch mechanism consists of a coil spring, roll pin, and safety catch which are assembled on the bolt carrier. The safety catch is disposed in proximity to the proximal end of the safety catch mechanism and having a first position wherein the safety catch engages the catch surface, or recess, of the firing pin in the rest position and a second position wherein the safety catch disengages with the recess to release the firing pin for movement out of the rest position. The coil spring places force on the distil end of the safety catch mechanism which rotates on the provided roll pin to biases the safety catch into the first position. The safety catch includes a camming surface on the distil end of the safety catch. Also, the camming surface is disposed within the motion path of the hammer. When the safety catch mechanism is in the first position such that, as the hammer moves from the cocked position through the travel path, the hammer cams the camming surface of the safety catch against the force being applied by the coil spring to move the safety catch from the first position to the second position, allowing the hammer to strike the proximal end of the firing pin thus forcing it forward into the primer of a loaded cartridge.
Other features and advantages are inherent in the disclosed apparatus or will become apparent to those skilled in the art from the following detailed description and its accompanying drawings.
The novel features believed to be characteristic of the invention, together with further advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which a preferred embodiment of the present invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.
Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, as used herein, the word “front” or “forward” corresponds to the end of the bolt carrier assembly where the bolt is located (i.e., to the left as shown in
The firing pin safety catch mechanism 10 disclosed herein is shown in
The bolt 31 has a first longitudinal receiving bore 34 formed therein to house the firing pin 20. A second longitudinal receiving bore 35 is formed in the front of the bolt carrier 30 to contain the bolt 31. The firing pin 20 is rearwardly biased into its rest position (shown in
When the hammer 32 makes contact with the rear of the firing pin 20, the firing pin 20 moves forward against the force of the firing pin spring 21 until the firing pin 20 is protruding far enough to ignite the primer of a loaded cartridge (not shown) as seen in
As illustrated in
The first longitudinal bore 34 is formed by the standard practices used to manufacture a bolt 31 for the M16 series of firearms. A round opening is present at both the proximal and distil ends of the first longitudinal bore 34 formed through the bolt 31.
The second longitudinal receiving bore 35 extends from the distil end of the bolt carrier 30 to approximately its mid point. The bolt 31 operates, in general, substantially similar to a prior art bolt in a prior art bolt carrier. The distil end of the second longitudinal bore 35 is open to receive the bolt 31 and at the proximal end to receive the firing pin 20.
The safety catch mechanism 10 has a portion, the safety catch 13, which is machined on the proximal end and protrudes into the path of the firing pin 20. The safety catch 13 has a camming surface 14 machined onto its proximal end which increasingly extends into the travel path of the hammer 32. The distil end of the safety catch 13 is positioned just to the side and behind the rear end of the firing pin 20.
In the rest position illustrated in
The outer end of the annular recess 22 and the rear end of the safety catch 13 facing the firing pin 20 are each preferably provided with a chamfer. The chamfers on these surfaces are complementary. If the firing pin 20 is not moved back into its rest position after a shot is fired, the firing pin spring 21 forces the firing pin 20 and thereby the recess 22 back until the safety catch 13 engages the recess 22 surface.
During reloading, the bolt 31 pushes a new cartridge from the magazine (not shown) forward, into the chamber of the barrel (not shown) until the bolt 31 seats against the proximal end of the chamber (not shown). As the bolt 31 contacts the barrel chamber it rotates within the bolt carrier 30. During this rotation of the bolt 31 the firing pin spring 21 is further compressed between the rear of the bolt 31 and the flange present along the distil end of the recess 22 located on the firing pin 20. This increase of tension applies additional force to the firing pin 20 thereby moving it into its rest position.
From the foregoing, persons of ordinary skill in the art will appreciate that the disclosed firing pin safety device for auto-loading firearms is advantageous with respect to other prior art firing pin safety devices in that, for example, it may be adapted, with minor modifications, to the exiting bolt carrier group used by the M16 family of firearms, further it has very few moving parts allowing for higher operational reliability. The herein disclosed device is readily implemented into the M16 family of firearms. In particular, the disclosed device achieves these objectives by implementing a safety element which is placed onto the exiting bolt carrier design and interacts with the prior art firing pin. All that is added are the safety catch mechanism 10, spring 11 and roll pin 12.
In principle, it is possible to produce a safety catch mechanism by machining the parts from unhardened steel billet, and to heat treat it to the desired hardness. Other technologies such as metal injection molding may be used to reduce the cost associated with machining the parts from billet. The spring may be produced from any heat resistant steel that is capable of repeatedly bearing a load. A roll pin of hardened steel may be purchased from any number of suppliers.
During assembly, a spring 11 is placed within a void located at the distil end of the guide groove 15. The safety catch mechanism 10 is placed in the groove 15 and depressed within. After the bore 36 for the roll pin 12 lines up with the void (not shown) in the safety catch mechanism 10, located proximately in its center, the roll pin 12 is driven into place. This orientation has the proximal end, where the safety catch 13 is located, protruding into the hollow within the bolt carrier 30. The guide groove 15 which houses the safety catch mechanism 10 supports the majority of its length to thereby prevent deflection during normal operation and to ensure reliable positioning of the safety catch 13 on the firing pin 20 recess 22. The remaining assembly necessary is identical to that which is required in the prior art.
Accordingly the reader will see that I have provided a firing pin safety device for auto-loading firearms which offers several advantages over the prior art. There herein, disclosed device prevents the unintentional discharge of a firearm which is the result of a “floating” firing pin. The herein described device will eliminate contact between the firing pin and the primer of a loaded cartridge which the firing pin is in contact with the safety catch mechanism. My device is designed to interact with the M16 family of weapons and the herein disclosures offers a means by which it may be incorporated, nevertheless this is not intended to limit the scope of this invention, rather, merely describe the preferred embodiment of the herein disclosed design.
While my above drawings and description contain much specificity, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof.
Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.
