Ordnance – Barrels – Silencers
Reexamination Certificate
2001-03-30
2002-07-02
Eldred, J. Woodrow (Department: 3644)
Ordnance
Barrels
Silencers
C181S223000
Reexamination Certificate
active
06412389
ABSTRACT:
RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §120 from PCT Application Ser. No. PCT/EP00/06894, filed Jul. 19, 2000.
FIELD OF INVENTION
The present invention relates generally to firearms, and particularly, to a retainer for securing a silencer on barrel of handgun. The retainer can be integral with the silencer, or may be affixed to the same. Likewise the retainer can be integral with the gun barrel, or may be affixed to the same.
BACKGROUND
In the following, “forward” (and its derivatives) is to be understood as “in the direction of firing.”
A retainer for a removable silencer for a handheld firearm must at a minimum fulfill two requirements. First, the retainer must be self centering, such that upon attachment, the longitudinal bore axes of the silencer and the barrel must exactly coincide. Second, the retainer attaching the silencer to the barrel must provide a gas tight seal relative to the combustion gases emitted from the barrel. These combustion gases exhibit the highest emission pressure in the area of the silencer. Upon firing, a slight failure in the seal can cause combustion gases to escape at supersonic speeds, thereby entering the surrounding atmosphere and producing a definite report.
Almost always, gas is emitted from the transitional zone between the cylinder and the bore of a revolver and gives rise to an expansion report, which reduces the action of a silencer to such a point, that as a rule, one refrains from equipping a revolver with a silencer.
To meet the self centering requirement, complementary, precision-fit cylindrical seating is typically provided on both the silencer and the barrel in a coaxial relation. The coaxial seating allows both parts to be pushed into one another with as little play as possible. For sealing against gas escape, as a rule, a fine threading is employed, which is at least several threads deep and thereby provides a sufficient, gas blocking labyrinth, as has been disclosed by DE 42 31 183 C1.
Since the process of screwing on the silencer is time consuming and requires a certain degree of digital dexterity in order not to damage the very fine threads, a precision fit can also be used instead of threads as a sealant for the combustion gas. To use a precision fit as a sealant, however, requires that the precision-fit zones formed by the complimentary cylindrical surfaces of the barrel and the silencer are long enough to prevent gas leakage, which might be caused by the pressure-instigated retractions of the precision fit surfaces. Additionally, any scratches and faults on the surfaces could further cause leaks. Thus, even with long enough precision fit surfaces, extensive firing of the weapon can eventually lead to gas leaks, which results in the presence of expansion reports.
The hurried pushing together of the two long, precision fit cylindrical components is not simple and thus attaching a precision fit silencer may take just as long as the above mentioned threaded attachment of the silencer. It is possible that jamming can happen, and indeed, it is very possible when the precision-fit cylinders have acquired dirt thereon. Additionally, powder residue which has deposited on the precision-fit surfaces especially obstructs the withdrawal of the silencer from the gun barrel.
From the foregoing, persons of ordinary skill in the art will appreciate that it is desirable to provide a retainer for a silencer on the barrel of a firearm, wherein the slipping on of the silencer onto the barrel is possible without encountering jamming or the like, and further, wherein pronounced expansion reports are eliminated.
Further, it is desirable to ease the withdrawal of the silencer from the barrel. In order to achieve the goal of easing the withdrawal of a precision-fit silencer from the barrel, certain practical steps are typically taken, including: (a) designing the cylindrical precision fit zone as long as possible in order to obtain a good centering and especially a good sealing, even if the precision-fit zone does not lead to a solid fit; (b) to the extent possible, making the precision-fit zone smooth and of unbroken continuity in order to provide an easy sliding together of the cylindrical surfaces; and, (c) designing a conical introductory stage, such that, upon entry of the silencer, the cylindrical surfaces align themselves with respect to one another before they reach touch-engagement in the precision-fit zone.
Such a retainer is necessarily rather long. Further, powder deposits, which accumulate in the precision-fit zone, still make the withdrawal of the silencer from the barrel of the firearm difficult, although this difficulty may be somewhat reduced if the precision-fit has sufficient looseness.
REFERENCES:
patent: 2101849 (1937-12-01), Green
patent: 4429614 (1984-02-01), Tocco
patent: 4530417 (1985-07-01), Daniel
patent: 4576083 (1986-03-01), Seberger, Jr.
patent: 4726280 (1988-02-01), Frye
patent: 4974489 (1990-12-01), Fishbaugh
patent: 5433133 (1995-07-01), La France
patent: 5679916 (1997-10-01), Weichert
patent: 2824546 (1979-12-01), None
Official Search Report of EPO/ISA from PCT/EP 00/06894.
Eldred J. Woodrow
Heckler & Koch GmbH
Marshall Gerstein & Borun.
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