Ordnance – Machine guns – Axially moving breech block
Reexamination Certificate
2000-06-06
2001-07-24
Johnson, Stephen M. (Department: 3641)
Ordnance
Machine guns
Axially moving breech block
C089S033160
Reexamination Certificate
active
06263776
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to aircraft armament apparatus and, in a preferred embodiment thereof, more particularly relates to the mounting of machine guns, representatively 30 mm machine guns, on light aircraft such as helicopters.
The external mounting on aircraft of weaponry such as machine guns has heretofore carried with it a variety of structural, operational and safety limitations and disadvantages. To a great extent these problems have been eliminated by using a honeycombed metal support plank such as that illustrated and described in U.S. Pat. No. 5,419,234 to Sanderson. As illustrated in such patent, 40 mm machine guns are mounted on opposite support plank ends which project outwardly from the cabin area of a helicopter.
A particularly difficult external aircraft mounting problem is presented by the much higher recoil 30 mm machine gun. In previously proposed nonplank-based external aircraft mounting systems for 30 mm machine guns, several problems, limitations and disadvantages have been present. For example, due to the high recoil forces generated by firing the 30 mm machine gun, their external aircraft mounts have tended to be quite complex—an undesirable characteristic arising from the need to protect the “light” helicopter (such as an MD 500 or Bell 206 helicopter) from structural damage from recoil forces, and to prevent loss of pilot control of the aircraft during gun firing. Attempts to design an external aircraft mount structure for the 30 mm machine structure have heretofore not been entirely successful in either of these areas.
Other problems, limitations and disadvantages presented in the use of both aircraft and ground-mounted 30 mm machine guns have to do with the construction and operation of the gun itself. The three primary areas of such problems, limitations and disadvantages in conventionally constructed 30 mm machine guns arise from (1) their complex construction, (2) their heretofore unavoidable high firing recoil forces, and (3) the difficulty in field servicing the guns.
The complex construction of traditionally configured 30 mm machine guns can lead to reliability problems and difficult and expensive fabrication operations. The high recoil forces of conventional 30 mm machine guns undesirably diminishes their firing controllability and accuracy and, as mentioned above, has made it quite difficult to mount 30 mm machine guns on light aircraft such as helicopters. Further, the difficulty in field servicing the guns typically requires that they be uncoupled from the aircraft and taken to a special maintenance facility to be worked on by a specialized technician having an aircraft mechanic/ordnance skill level. This has been true even for routine gun cleaning and maintenance services. Additionally, to simply clean a conventionally constructed 30 mm machine gun it has to be taken nearly completely apart—a tedious task entailing removing countless screws, bolts and other fasteners and then replacing them after the gun cleaning task is completed.
From the foregoing it can readily be seen that a need exists for a 30 mm machine gun that eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages commonly associated with 30 mm machine guns of conventional construction. It is to this need that the present invention is directed.
SUMMARY OF THE INVENTION
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, a machine gun, representatively a 30 mm machine gun, is provided with a variety of unique structural and operational features which serve to (1) reduce the complexity of the gun, (2) make it relatively easy to service in the field, and (3) substantially reduce its recoil to thereby facilitate its mountability on light aircraft such as helicopters, and improve its firing controllability and accuracy. The gun is illustratively secured, via a rollered mounting cradle, to the outer end of a support plank structure extending transversely through the cabin area of an aircraft, but may be supported in other manners in a variety of other aircraft and ground-based mounting applications.
In its preferred embodiment, the machine gun basically comprises a body upon which a barrel is mounted, the barrel longitudinally extending forwardly and rearwardly along a firing axis. The body is supported by a cradle and feed structure unit for rearward recoil movement and forward counter-recoil movement relative to the cradle and feed structure unit in response to the firing of the gun. The feed structure part of the unit is operative to position successive cartridges for retrieval and chambering in the barrel for firing therein. An operating rod structure is carried by the body for driven movement relative thereto cyclically in forward and rearward directions in response to firing of the gun, and a resilient recoil system is provided for absorbing the rearward recoil and forward counter-recoil forces of the gun. Firing apparatus is provided for firing each chambered cartridge, the firing of each cartridge causing a rearward recoil movement and subsequent forward counter-recoil movement of the gun body relative to the stationary feed and cradle apparatus.
Ammunition handling means are carried by the gun body and are operative to deliver cartridges from the feed structure to the barrel for firing therein, and then extracting and ejecting the spent casings of the fired cartridges. Representatively, the ammunition handling means include a bolt member carried by the operating rod structure rearwardly of the feed structure for cyclical forward and rearward movement with the operating rod structure toward and away from the feed structure, the bolt member having first and second extractor means thereon for releasably receiving and retaining rear cartridge casing rim portions.
A bolt face member is carried by the bolt member for movement relative thereto in first and second opposite directions transverse to the barrel, the bolt face member having ejector means thereon for releasably circumscribing a rear cartridge casing end portion. Cooperating means are provided on the bolt face member and the gun body for moving the bolt face member in the first direction relative to the bolt member in response to movement of the bolt member toward the feed structure, and for moving the bolt face member in the second direction relative to the bolt member in response to movement of the bolt member away from the feed structure. Representatively, these cooperating means include a cam track formed in the body with a pivotally spring-loaded switch plate member attached, and a roller structure carried on the bolt face member and received in the cam track for guided rolling movement therealong.
The relatively simple bolt member/bolt face member structure performs several ammunition handling functions during the firing of the gun—namely, (1) extracting a first cartridge from the feed structure, (2) chambering the extracted first cartridge in the barrel, (3) extracting a second cartridge from the feed structure while extracting the spent casing of the first cartridge, after firing thereof, from the barrel, and (4) moving the extracted second cartridge into a chambering alignment position in a manner causing the extracted second cartridge to engage and forcibly eject the spent casing from the ammunition handling means by ejectors mounted on the bolt face member.
Cooperatively engaged first and second structures are respectively disposed on the gun body and the feed structure for operating the feed structure in response to forward and rearward movement of the gun body relative to the stationary feed structure. Because the movement of the gun body relative to the feed apparatus operates the feed apparatus, no complicated timing system is needed.
Representatively, a cam track slot having an angled central portion is formed in a top side portion of the gun body and slidingly receives a cam follower pin which depends from a rotatable feed drum portion of the feed structure. The
Johnson Stephen M.
Konneker & Smith P.C.
Sanderson Paul H.
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