US Patent 8961499 Surgical instrument

A surgical instrument having an elongated arm and a distal end mounted with a pivot joint on the elongated arm. A drive shaft substantially coaxial with the elongated arm forms a universal joint facing the pivot joint. A distal tool is securely fastened on the drive shaft and rotatively mounted on and in the extension of the distal end of the elongated arm, such that the distal tool has two rotational degree of freedom, distinct and independent of each other, one being around an axis substantially perpendicular to the longitudinal axis of the elongated arm and the other being around an axis substantially collinear to an own axis of the distal tool. The elongated arm includes a plurality of linking elements mounted in series to form the pivot joint. The universal joint is a Cardan joint.