Abstract: A surgical instrument for minimally invasive surgery has an instrument shaft with a distal end and a proximal end. The proximal end is connectable to a signal generator. The surgical instrument has an instrument head which is pivotably connected to the distal end of the instrument shaft via a joint, and an end effector which is mounted rotatably about its longitudinal axis in the instrument head. The instrument further comprises a mechanical coupling element which is arranged at least partially in the instrument shaft and is configured to transmit and/or convert mechanical actuating signals of the signal generator for pivoting and rotating the instrument head, as well as a coil spring which bypasses the joint and connects the end effector to the coupling element to rotate the end effector. The coil spring has portions with different spring constants.

Abstract: A surgical instrument for minimally invasive surgery has an instrument shaft with a distal end and a proximal end. The proximal end is connectable to a signal generator. The surgical instrument has an instrument head which is pivotably connected to the distal end of the instrument shaft via a joint, and an end effector which is mounted rotatably about its longitudinal axis in the instrument head. The instrument further comprises a mechanical coupling element which is arranged at least partially in the instrument shaft and is configured to transmit and/or convert mechanical actuating signals of the signal generator for pivoting and rotating the instrument head, as well as a coil spring which bypasses the joint and connects the end effector to the coupling element to rotate the end effector. The coil spring has portions with different spring constants.