Brevets Aero-Mecaniques, SA v. Marzall

• Decision Date: 13 May 1952
• Docket Number: No. 1305-51.,1305-51.
• Citation: 104 F. Supp. 591
• Parties: BREVETS AERO-MECANIQUES, S. A., et al. v. MARZALL, Commissioner of Patents.
• Court: U.S. District Court — District of Columbia

104 F. Supp. 591

BREVETS AERO-MECANIQUES, S. A., et al. v. MARZALL, Commissioner of Patents.

No. 1305-51.

United States District Court District of Columbia.

May 13, 1952.

Roberts B. Larson, Washington, D. C., for plaintiffs.

E. L. Reynolds, Solicitor, Washington, D. C., for defendant.

TAMM, District Judge.

This is an action under Section 4915 of the Revised Statutes, Section 63, Title 35, U.S.C.A. The plaintiffs seek an adjudication that they are entitled to a patent on certain improvements in an Actuating Device for the Unlocking Control Used in Automatic Arms with Gas Tapping.

Plaintiff, Brevets Aero-Mecaniques, S. A., is a corporation organized and existing under the laws of Switzerland, and has an office and place of business in Geneva, Switzerland. It is the assignee by assignment of the plaintiff, Bernard Maillard, of the application for a patent involved herein. Plaintiff, Maillard, is a Swiss citizen and a resident of Geneva, Switzerland. The defendant is the Commissioner of Patents of the United States.

The plaintiffs have duly prosecuted their application for Letters Patent in the Patent Office. The serial number assigned to their application is 609,836. Upon final rejection of their claims by the Primary Examiner, the plaintiffs appealed to the Board of Appeals of the Patent Office. After a hearing on the appeal, the Board of Appeals, in a decision rendered on December 19, 1950, sustained the action of the Examiner in rejecting the claims of the application.

Although ten claims were presented to the Patent Office by the plaintiffs only two claims, numbers 8 and 9, are before this Court. A statement of these claims follows:

8. In an automatic firearm, a breech mechanism including a breech casing, a barrel, means for detachably securing said barrel to said breech casing, said means requiring rotation of said barrel with respect to said casing for fixation thereto and removal therefrom, means for transmitting energy from the inside of said barrel to said breech mechanism, said last-named means including at least two cooperating elongated parts disposed parallel to said barrel and carried one solely by said barrel and one solely by said breech casing, means for mounting said cooperating elongated parts each for sliding movement in the longitudinal direction and in such radial positions as to be located end to end when the barrel is on the breech casing in the assembled position, the contacting respective ends of said parts being at all times freely slidable in the transverse direction with respect to each other whereby instantaneous fixation and removal of the barrel with respect to the breech casing can be carried out without interference from said parts.

9. A combination according to claim 8 including a small cylinder carried by said barrel and communicating with the inside thereof, said cylinder being closed toward the front, the elongated part carried by the barrel consisting of a rod the front end of which is engaged in said cylinder to form a piston therein.

The plaintiffs contend that the rejection of these claims by the Patent Office was erroneous and ask this Court to issue a decree adjudging that they are entitled to a patent for the alleged invention defined in the claims.

In order that the precise nature of the claimed invention might be more readily understood, a brief description of the problem which the plaintiff, Maillard, sought to resolve is set forth.

When automatic weapons with a high rate of firing are shot for some time, the barrel becomes dangerously hot.¹ If the use of the gun is required after the barrel has become critically heated, the operator of the piece is faced with a choice of one of three courses of action: (1) continue to fire the gun with the practical certainty of either permanently incapacitating it or damaging it to such an extent that time-consuming repairs are required; (2) leave the gun inactive until the barrel has cooled off sufficiently for the gun to be safely put into use again, or (3) remove the hot barrel and mount a cold barrel. Obviously the first two choices are not desirable, particularly during combat. Where the gun bears a gas tapping device mounted on the barrel and the breech casing, and the barrel is joined to the breech casing by screw threading, the third choice is equally undesirable according to the plaintiffs. For the substitution of barrels requires the removal and subsequent remounting of a part of the gas tapping device. An expert witness for the plaintiff testified at the trial that the exchange of barrels for this type weapon requires the services of men skilled in this delicate work and takes from one to three hours to complete. The plaintiffs' alleged invention will facilitate the exchange of barrels for this type gun, for, according to their design, it will no longer be necessary to remove any part of the gas tapping device in substituting one barrel for another, and the time required to complete the substitution will be only about ten seconds.

The purpose of a gas tapping device is to utilize the gas pressure built up in the barrel when the projectile leaves the cartridge case to unlock the breechblock lock and retract the firing pin. This is accomplished by having the gas pressure referred to bled through a minute opening in the gun barrel into a cylinder mounted on the top of the barrel. Upon entering the cylinder this pressure forces back a piston contained therein in such a manner as to activate a push rod (or push rods) that passes through the front end of the receiver and initiates the unlocking of the breechblock lock. Since the gas required for the unlocking is taken from the barrel and the unlocking of the breechblock necessarily takes place in the breech casing, it follows that a mechanical means of transmission of the motion between the barrel and the breech casing cannot be avoided.

The Court does not think it necessary to present a detailed delineation of the construction and mounting of the conventional gas tapping device. It is sufficient to state that heretofore automatic weapons with gas tapping having a barrel attached by screw threading to the breech casing were so constructed that the gas cylinder bridged the barrel and breech casing in such a way that it was impossible to remove the barrel without first removing the gas cylinder. In other words, it was impossible, under conventional design, to rotate the barrel of the gun about its axis while the gas cylinder was mounted on the gun because of the mechanical fixation of the barrel and the breech casing caused by the cylinder. The design set out in the claims of the plaintiff permits such rotation of the barrel in the transverse...