Patent attributes
A cartridge includes a cartridge case having a shell having a first end portion, a second end portion opposite the first end portion and a cylindrical body extending from the first end portion to the second end portion. A reinforcing cap includes a base, a sidewall extending from the base and surrounding the first end portion such that the first edge of the shell abuts an inner face of the base, and a projection extending from the inner face. A ring is pressed against the inner face and forms an air-tight seal between the projection, the inner face, the ring, and the first end portion of the shell. A plurality of indentations form protrusions in the sidewall and the first end portion for interlocking the reinforcing cap to the shell and retaining the ring against the inner face of the base.
