Patent ID: 7479083

Claim:
Gear mechanism ( 10 ) comprising a spur wheel ( 14 ) which is provided with external teeth ( 16 ) and meshes with an internal gear ( 18 ) that is provided with internal teeth ( 20 ), wherein the number of internal teeth ( 20 ) to generate a certain gear step-up ratio is greater by at least one than the number of external teeth ( 16 ) and the spur wheel ( 14 ) and the internal gear ( 18 ) perform an eccentric movement relative to one another, characterized in that the eccentric movement is directed by means of the matching tooth geometry of the internal and external teeth ( 20 , 16 ), and wherein the outside diameter ( 64 ) of the external teeth ( 16 ) is greater than the inside diameter ( 66 ) of the internal teeth ( 20 ).