Cylindrical breech with sleeved obturator

Claim 2

In a gun, a movable breech means movable between a firing position and a loading position, a firing chamber in said movable breech means, radially expandable and contractable sleeve means mounted on said movable breech means and having an inner cylindrical pressure applying surface and an outer cylindrical obturating surface and being movable radially relative to the breech means between a contracted position during movement of the breech means and an expanded obturating position during firing of the gun, and passage means connecting said firing chamber to said pressure applying surface of said sleeve means to carry high pressure gas from the firing chamber to the pressure applying surface and radially expand the sleeve means to the obturating position.

Claim 3

The invention as defined in claim 1 and wherein: said breech means comprising a cylindrical seat extending beyond all sides of said firing chamber, and aid expandable sleeve means being mounted on said cylindrical seat.

Claim 4

The invention as defined in claim 2 and wherein said passage means comprises a centrally located passage means extending transversely from said firing chamber within said breech means, and cross passage means extending transversely to said centrally located passage means and opening on said cylindrical seat onto said expandable sleeve means.

Claim 5

The invention as defined in claim 3 and wherein said sleeve means being fixed to said breech means beyond said cross passage means.

Claim 6

In a gun, barrel means through which the ammunition is fired, a source of high pressure high temperature air, a cylindrical slide chamber located behind said barrel means, a movable breech means mounted behind said barrel means and being movable between a loading position and a firing position and having a cylindrical portion thereof located in alignment with said barrel means in the firing position and slidably supported within said slide chamber, a firing chamber in said cylindrical portion of said movable breech means for holding a round of ammunition in a firing position in alignment with said barrel means, radially expandable cylindrical sleeve means mounted on said movable breech means and being movable therewith between the loading position and the firing position and being movable relative thereto in the firing position between a transfer position substantially abutting said cylindrical portion and an obturating position sealingly engaging said cylindrical side chamber, there being space circumjacent and between said cylindrical sleeve means and said movable breech means for introduction of high pressure gas providing a sleeve means expanding force, and passage means connecting said firing chamber to said space to deliver high pressure gas thereto for outwardly expanding said sleeve means to the obturating position.

Claim 7

In a gun, barrel means through which the ammunition is fired, a source of high pressure high temperature air, a cylindrical slide chamber located behind said barrel means, a movable breech means mounted behind said barrel means and being movable between a loading position and a firing position and having a cylindrical portion thereof located in alignment with said barrel means in the firing position and slidably supported within said slide chamber, a firing chamber in said cylindrical portion of said movable breech means for holding a round of ammunition in a firing position in alignment with said barrel means, radially expandable cylindrical sleeve means mounted on said movable breech means and being movable therewith between the loading position and the firing position and being movable relative thereto in the firing position between a transfer position substantially abutting said cylindrical portion and an obturating position sealingly engaging said cylindrical side chamber, there being space circumjacent and between said cylindrical sleeve means and said movable breech means for introduction of high pressure gas providing a sleeve means expanding force, and passage means connecting said firing chamber to said space to deliver high pressure gas thereto for outwardly expanding said sleeve means to the obturating position.

Claim 8

The invention as defined in claim 5 and wherein: said firing chamber comprising an enlarged diameter bore portion next adjacent said source of air and a reduced diameter bore portion next adjacent said barrel means and a transverse shoulder connecting said enlarged diameter bore portion to said reduced diameter bore portion, said passage means comprising transverse passage means intersecting said enlarged diameTer bore portion at a location axially spaced from said transverse shoulder a distance sufficient to locate the exposed portion of the projectile to be fired from said firearm beyond said transverse passage means toward said barrel means whereby to prevent obstruction of said transverse passage means by the projectile.