Eccentric planetary gearing

An eccentric planetary gearing comprising two internally toothed gears, a double-ring externally toothed planetary gear and a planet carrier;

• said double-ring externally toothed planetary gear having the design of a cluster gear comprising two externally toothed gear rings of different diameters coaxially aligned and consecutively disposed relative to one another;
• said internally toothed gears being coaxially aligned and consecutively disposed relative to one another and their common axis being central axis of the gearing;
• one of said internally toothed gears being mounted for rotation and the other being held in a fixed position;
• said planet carrier being mounted for rotation about the central axis of the gearing;
• said double-ring externally toothed planetary gear being rotatably mounted on said planet carrier;
• the axis of said double-ring externally toothed planetary gear being parallel to and offset from the central axis of the gearing, the respective eccentricity being less than the outside radius of said double-ring externally toothed planetary gear, the central axis of the gearing lying, accordingly, inside the periphery of said double-ring externally toothed planetary gear;
• each of said internally toothed gears being in meshing engagement with a respective gear ring of said double-ring externally toothed planetary gear;
• said planet carrier comprising support means for providing the rotatable mounting of said planet carrier itself and the rotatable mounting of said double-ring externally toothed planetary gear, said support means being integrated into a rigid member through two interjacent crescent-shaped sections consecutively disposed relative to one another;
• each of said interjacent crescent-shaped sections being disposed within the space between the respective gear ring of said double-ring externally toothed planetary gear and the respective internally toothed gear;
• orthogonal projections of said interjacent crescent-shaped sections on a plane perpendicular to the central axis of the gearing being of different disposition relative to one another and, accordingly, at least one of the outer and the inner surfaces of said planet carrier being step-shaped along the junction of said interjacent crescent-shaped sections.