Firearms – Firing mechanism
Reexamination Certificate
2000-04-20
2002-02-19
Poon, Peter M. (Department: 2643)
Firearms
Firing mechanism
C042S069030
Reexamination Certificate
active
06347474
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to firearms, and more specifically to a trigger return system for firearms.
BACKGROUND OF THE INVENTION
There are many different types of firearm actions. The action defines how the gun is constructed and how it functions. The action defines, at least in part, how the trigger is pulled, what happens mechanically to cause the firing pin to strike the cartridge's primer, how the empty casing is removed from the firing chamber, and how the next cartridge is placed into the firing chamber for the next shot.
For example, a handgun is generally either a revolver or a semiautomatic. There are, of course, other types of actions, but most handguns on the market today are either revolvers or semiautomatic. The revolver predated the semiautomatic in the development of handguns. At the very least, all typical revolvers have a frame, a hammer, a trigger, a cylinder, a barrel, and a firing pin. The cylinder holds several cartridges, each in its respective chamber. As the cylinder rotates during operation of the gun, each chamber takes its turn in line with the barrel. As the firing pin is actuated through the user's pulling of the trigger, the drop of the hammer causes the firing pin to strike the cartridge's primer, igniting the powder in the cartridge's casing, thus expelling the projectile, first through the barrel and ultimately toward the target.
After a shot is fired from the revolver, the cylinder must rotate to bring the next chamber which contains a cartridge in line with the barrel. Generally, this process is repeated until all bullets have been fired, at which point the empty casings can be removed and replaced with live rounds.
There are two well-known revolver actions, each of which applied to revolvers during their development. These are known as “single action” and “double action.” The single action revolver was the first general type of revolver developed. This firearm required that the hammer be manually pulled, or cocked, each time the gun was to be fired. By cocking the hammer, the user of the pistol caused the cylinder to rotate and thereby bring the next chamber in line with the barrel. When the trigger was pulled, the hammer fell, causing the firing pin to strike the ignition system and fire the gun. For the next shot to be fired, the hammer was again cocked, usually with the user's thumb, which rotated the cylinder, and the gun could be fired again.
The second type of action was developed later. This action became known as the “double action” revolver. In this case, the hammer did not have to be cocked by hand prior to pulling the trigger. The user of a double action revolver could simply pull the trigger and the gun would fire. The pulling of the trigger caused two actions to occur. The first part of the trigger pull caused the hammer to cock itself, while simultaneously the cylinder rotated, bringing the next chamber in line with the barrel. The second part of the same trigger pull resulted in the hammer falling and the striking of the ignition system. Thus, the term “double action” was adopted to describe the “double action” achieved by pulling the trigger. The hammer was cocked and dropped, sequentially, with a single pull of the trigger.
The double action revolver could, however, be cocked by hand, just as a single action revolver must be cocked by hand. In such a case, a slight pull of the trigger on the double action revolver would then fire the gun as in the case of the single action.
Conventional semiautomatic handguns were developed as early as the beginning of the 1900's. Semiautomatic handguns can, generally, be distinguished from a revolver in that the expended cartridge casing is expelled from the gun and the next cartridge is brought into the firing chamber “automatically” upon firing the gun. Various mechanisms for accomplishing this objective, including gas pressure, recoil operated, and blow-back designs, have been developed.
Generally, the semiautomatic firearm action provides a mechanism for ejecting a spent casing from the gun completely, immediately after that round is fired. As a part of the mechanics for ejecting the spent shell, the next cartridge is fed into the firing chamber and the gun is ready to be fired again. Typically, the first shot fired from the semiautomatic does not require that the gun's hammer be manually cocked as in the case of a single action revolver. The user may cock the hammer manually, and then pull the trigger, or may pull the trigger which will, as in the case of the double action revolver, cock the hammer and then allow the hammer to fall, all in one pull of the trigger. Thus, borrowing terminology from its predecessors, the semiautomatic firearm which could be fired for the first time simply with a pull of the trigger (without cocking the hammer manually) was dubbed a “double action semiautomatic.” The focus of the terminology was the first shot fired from the gun in a series of shots. Thus, when the hammer is down, it may either be cocked manually, or not, depending on the choice of the user.
Usually, after the first shot is fired, that casing is expelled, the next round is brought into the firing chamber, and the hammer is cocked for the next shot, all in one cycle. Thus, the hammer is automatically cocked after each shot of the double action semiautomatic firearm, ready to be dropped again by the next pull of the trigger. For most of the development of the semiautomatic firearm, until recently, there was no semiautomatic firearm in which the hammer always stayed uncocked after each and every shot.
Recently, the “double action only” semiautomatic firearm (“DA only”) was developed. This mechanism is different from earlier semiautomatic firearms in that each time the “DA only” is fired, the mechanism cycles but the hammer comes to rest in the uncocked position. There is no way to cock the “DA only” first, as was the case in single action revolvers, double action revolvers, and double action semiautomatics. A bit of a confusing term, the “DA only” mechanism simply means that the gun cannot first be manually cocked by the user, prior to pulling the trigger. Many “DA onlys” do not even have an exposed hammer. In such a case, the hammer is inside the frame of the gun.
The “DA only” was developed largely for law enforcement and self-defense purposes. Because a gun whose hammer remains cocked requires, in almost all cases, relatively light pressure on the trigger to be fired (as opposed to when it is uncocked and the trigger pull serves first to cock the gun), it was thought by some that in a high-stress situation, the likelihood of an accidental firing was increased where a semiautomatic's hammer was automatically cocked after each shot. Where, on the other hand, the trigger needs to be pulled through its entire range each and every time the gun is to be fired, some thought the likelihood of an accidental discharge was diminished.
With the development of the “DA only”, and its subsequent adoption by many governmental agencies, many training standards were developed for its use by the agents. One problem with the “DA only” is that the user must exert a relatively large amount of force on the trigger each time a shot is needed. Thus, when the user wishes to fire rapidly over a length of time, the user's hand and finger often get fatigued.
This was especially true in the case of many Beretta® (Beretta is a registered trademark of Beretta U.S.A. Corp.) pistols. One factor in trigger finger fatigue can be attributed to the spring which returns the trigger to its forward position after the shot is fired. The more rigid the spring, the more strength is required to pull the trigger through its cycle.
Another problem with some conventional “DA only” trigger return springs is that they can prematurely fail, particularly where torsion springs are utilized, rendering the gun effectively useless. This is, of course, especially problematic and dangerous in the case of law enforcement and self-defense.
Thus, an improved trigger return
Piascik Susan
Poon Peter M.
Ratner & Prestia
Spadt Jonathan H.
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