with piston rotating around an axis passing through the gravity centre, this piston or the housing rotating at the same time around an axis parallel to the first axis

Full Title

Internal-combustion engines with pistons rotating or oscillating with relation to the housing > with one or more pistons in the form of a disk or rotor rotating with relation to the housing; with annular working chamber > with piston rotating around an axis passing through the gravity centre, this piston or the housing rotating at the same time around an axis parallel to the first axis