Keyless tool shaft coupling

A keyless coupling for a tool shaft and a handpiece of a surgical instrument, comprising a first coupling portion provided at a proximal portion of the tool shaft, a second coupling portion provided at a distal portion of a shaft receptacle of the handpiece, and a locking/unlocking element, wherein:

• the locking/unlocking element is arranged on the tool shaft and forms a latch portion and the shaft receptacle comprises at least one recess provided and adapted to receive the latch portion in a locking position of the first and second coupling portions so that the latch portion and the at least one recess are in latching engagement with each other and secure the first and second coupling portions against relative axial movement with respect to each other in a pulling direction and in a circumferential direction, wherein:
• the locking/unlocking element is preloaded in the locking position by a preloading element in a direction radially outward of the tool shaft,
• the tool shaft has a groove extending substantially in its longitudinal direction, wherein the groove is provided and adapted to receive the locking/unlocking element along its entire length;
• and
• the locking/unlocking element is arranged at its distal end to be rotatable about a pivot axis in the groove, so that the locking/unlocking element is pivotable out of and into the groove.