Patent ID: 8591519

Claim:
A surgical instrument for applying a rotational force to a structural element comprising: a housing, an input mechanism, and an output shaft that are each aligned along a longitudinal axis; the input mechanism including an eccentric shaft with a first section that extends axially on the longitudinal axis and a second section that is radially offset from the longitudinal axis, the input mechanism being rotatable relative to the housing; the output shaft extends axially on the longitudinal axis and includes a receptacle configured to engage with the structural element, the output shaft being rotatable relative to the housing; and a cycloidal gear system including: first and second annular members that are axially spaced along the longitudinal axis, each of the annular members having an opening aligned on the longitudinal axis and teeth that radially extend inward towards a center of the opening, the first annular member has a different number of teeth than the second annular member; first and second gears that are axially spaced along the longitudinal axis with the first gear aligned to engage with the first annular member and the second gear aligned to engage with the second annular member, each of the gears having teeth that radially extend outward away from the longitudinal axis and engage with the teeth on the respective annular members, the gears being connected to the second section of the eccentric shaft, the first gear having a different number of teeth than the second gear; one of the annular members being non-rotatably attached to the housing and the other of the annular members being rotatably attached to the housing.