Ordnance – Automatic – Blow back breech block
Reexamination Certificate
2001-07-27
2003-07-08
Johnson, Stephen M. (Department: 3641)
Ordnance
Automatic
Blow back breech block
C089S033100
Reexamination Certificate
active
06588312
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns an automatic firearm with a bolt assembly that moves along a motion path between a closed position and an open position with a magazine that conveys, by spring force or the like, cartridges in sequence into an advance position across the motion path of the bolt assembly, in which the first or uppermost cartridge protrudes at least partially into the bolt assembly motion path.
BACKGROUND OF THE INVENTION
As used herein, when position terms like “top”, “vertical” or the like are used, a weapon in the normal firing position is always assumed in which the barrel is horizontal. Similarly, “forward” is in the direction of shooting. Examples of automatic weapons are disclosed in U.S. Pat. Nos. 3,054,206; 3,120,070; 3,123,927; German Patent Nos. 532615 and 1811246; and French Patent No. 461816.
In automatic weapons of the type just mentioned, for example, with a clip magazine, the first or uppermost cartridge is forced by the magazine spring against the bolt assembly or behind the bolt assembly in its motion path when the bolt assembly is in the closed position. If, as a result of firing, the bolt assembly returns to its open position, it rubs against the uppermost cartridge until it approaches its open position. Only in such a position can the uppermost cartridge be advanced into its advance position. In this position, it is held by at least one magazine lip and is situated at least partly in front of the bolt assembly.
If the bolt assembly then moves forward again into its closed position, it pushes the cartridge from the rear into the cartridge chamber, in which the cartridge follows a more or less pronounced zig-zag path. This zig-zag path is flatter, the farther the advance position is situated in the motion path of the bolt assembly. The flatter this zig-zag, the more gentle the transport of the cartridge and the lower the likelihood of jamming. However, the first cartridge is also forced more vigorously by the magazine spring against the moving bolt assembly. If the cartridge is mechanically sensitive, say, a shotgun cartridge with a cardboard casing, it can be damaged during reloading. This is one of the reasons why automatic hunting shotguns employ a tubular magazine which conveys the first cartridge onto a loading spoon, on which it lies loosely beneath the moved bolt assembly and only then pivots into the motion path of the bolt assembly when it is open. Automatic shotguns for police use, on the other hand, which have a clip magazine, cannot fire such sensitive ammunition free of disturbance for this reason.
A generic automatic weapon is also a drawback for sports shooters who repeatedly reload a spent cartridge casing. The bolt assembly sliding along the pushed cartridge necessarily scratches its casing and damages it so that it can be reloaded less often than, say, the casing of a cartridge that is fired from a single-shot weapon.
Scratching of the projectile in a sharpshooter's weapon can lead to a reduction in shooting accuracy. This scratching of the projectile and casing is particularly serious when the bolt head has downward protruding sharp-edged protrusions and projections, like the US M16 military weapon.
So-called intelligent ammunition has recently been developed. This is ammunition for firearms whose projectile accommodates electronics that influence the behavior of the fired projectile. Thus, it is possible by means of target electronics mounted on the weapon to communicate to a spin-stabilized projectile the distance at which it is to detonate on firing. The target electronics then determines the distance to the target and informs the projectile of the number of revolutions that it must execute up to the target. The projectile electronics counts the actual projectile revolutions and ignites an explosive charge on reaching the stipulated number. In this ammunition the cartridge casing accounts for only about 40% of the cartridge length. The projectile equipped with the electronics has a length of about ⅔ of the cartridge length. The projectile shell need not serve as twisting guide and fragment shell in this projectile, but merely as covering. A plastic ring on the rear of the projectile, which also offers sealing relative to the propellant, like a propellant reflector, causes twist guiding. This type of projectile shell is naturally sensitive to mechanical damage.
The described projectile is sensitive in another respect: it cannot always be avoided that the bolt mechanism, which consists of steel, will become slightly permanently magnetic with time. In its material selection, the mechanical properties have absolute priority over any magnetic properties. The hazard of bolt mechanism magnetization exists, especially after longer storage of the weapon, in an arsenal in which the bolt mechanism lies for a longer time with unchanged alignment in the earth's magnetic field. Noticeable permanent magnetization can occur because of this. If this bolt mechanism is more or less strongly magnetized and moved directly past the projectile, it can induce interfering voltages in the projectile electronics. These can adversely affect the electronics. It is expressly pointed out that the invention concerns only those automatic weapons in which the first cartridge is still situated in the magazine in its advance position, i.e., a position in order to be introduced directly into the cartridge chamber of the barrel. Automatic weapons are known in which the advance position of the first cartridge does not coincide with its uppermost position in the magazine. In such weapons, the first cartridge, for example, is initially conveyed by means of an additional mechanism into a waiting position and only then into the advance position after removal from the magazine or a belt.
SUMMARY OF THE INVENTION
Starting from the problem outlined above, the underlying task of the disclosed apparatus is to modify the automatic firearm mentioned at the outset so that the cartridge, especially the projectile, retains its integrity as much as possible during reloading. It would also be advantageous to reduce any effect of a possible magnetized bolt assembly on a projectile with electronics.
This task is solved according to the disclosed apparatus since the automatic firearm mentioned at the outset has a lock releasable by the bolt mechanism, which initially holds back the first cartridge before it enters the motion path of the bolt assembly and is only released by the bolt assembly to advance this cartridge when the bolt assembly approaches its rear end position or open position.
Because of this, the bolt assembly can return without touching the cartridge to be advanced next or without scratching it. Only when the bolt assembly has traveled past the cartridge, at least its projectile, is the cartridge released by the lock, snaps upward into the advance position and can then be grasped by the bolt assembly moving forward again and reloaded. The cartridge in the weapon according to the disclosed apparatus does not lie against the bolt assembly during return of the bolt assembly, but is spaced from it, if only by a limited amount. This limited distance, however, can be sufficient to adequately reduce any magnetic influences of the bolt assembly on the projectile electronics.
REFERENCES:
patent: 2659994 (1953-11-01), Yale
patent: 3054206 (1962-09-01), Raleigh
patent: 3120070 (1964-02-01), Reed
patent: 3123927 (1964-03-01), Katz
patent: 4391055 (1983-07-01), Kadim
patent: 4567810 (1986-02-01), Preston
patent: 181871 (1907-04-01), None
patent: 532615 (1931-08-01), None
patent: 1811246 (1969-11-01), None
patent: 0 319 261 (1989-06-01), None
International Search Report for parent PCT Application No. PCT/EP00/00599, report dated May 29, 2000.
Fischbach Wilhelm
Murello Johannes
Weldle Helmut
Heckler & Koch GmbH
Johnson Stephen M.
Marshall Gerstein & Borun
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