Ring manufacture, productive of face contact seal

Piston wherefor sealing is accomplished by split piston ring means which, in collapsed state, become closed or substantially so in operation, said piston having:

• a groove and a split seal ring therein;
• said groove having a side which confronts that one side of the ring that is sealed thereby and which is planar or substantially so;
• said ring operatively arranged so that said one side is generally frusto conical when the ring is in collapsed state, said one side as viewed in cross section in that state having a narrow seal band at the inner periphery, which is a substantially lesser portion forming an angle of intersection with the major portion of said one side and which is effective during operation to establish a substantially continuous ring of pressure contact with the aforementioned confronting side of the groove which is sealed thereby in the manner described;
• said major portion of the one ring side being limited to no more bands than about 10 to 5 bands of flatness when the ring is compressed into flattened state while so collapsed, and operatively arranged when the major portion of the side is compressed into flattened state while the ring is so collapsed to establish a substantially uninterrupted pressure ring of face contact with, when contacted by, said surface which is sealed thereby in the manner described.

In an engine wherein sealing is accomplished by split piston rings which, in collapsed state, become closed or substantially so as when sealing in operation:

• piston having a ring-receiving groove;
• split ring therein having at least one side, and a face and a back adjacent the side and respectively adjoining same at the side of the ring and forming corners therewith at that side;
• said receiving groove having a side which confronts the said one side of the ring so as to be sealed thereby and which is planar or substantially so;
• said ring operatively arranged whereby said one side is generally frusto conical when the ring is in collapsed state, said one side as viewed in cross section in that state having a narrow seal band at the inner periphery, which is a substantially lesser portion forming an angle of intersection with the major portion of the side, and which is effective during operation to establish a substantially continuous ring of pressure contact with the confronting side of the groove sealed thereby;
• said major portion of the ring side being flat to at least about 10 to 5 light bands of lapped flatness when compressed into flattened state while so collapsed, and operatively arranged when the major portion of the side is compressed into flattenend state while the ring is so collapsed to establish a substantially uninterrupted pressure ring of face contact with, when contacted by, said confronting side of the groove sealed thereby;
• and
• a cylinder slidably receiving the piston and engaging the face of the ring to retain the latter at all times in collapsed state on the piston.