A tool, which is detachably coupleable with a shaft for a micro-invasive surgical instrument, includes an articulated device on which a jaw member or other active device is affixed, a connecting component that is rotatably connected with the articulated device and that includes a coupling device for detachable coupling with a distal end of a shaft, a transmission rod to transmit at least either a force or torque from one proximal end of a shaft detachably coupled with the tool to the jaw member or other active device, and a locking device that is coupled with the transmission rod in such a way that the locking device can be rotated with respect to the transmission rod but not slid axially, so that the locking device is mounted in the connecting component in such a way that it can be axially slid but not rotated in relation to the connecting component.
