Bayonet coupling for detachable joining of two tubular shaft instruments or instrument parts

A bayonet coupling for detachable joining of two tubular-shaft instruments or two instrument parts, comprising

• a bayonet sleeve extending along a longitudinal axis and having a bayonet guide which is provided on a first instrument part, said bayonet guide having a distal end formed with an axially extending slot which continues in a transverse slot spaced from a proximal end of the bayonet guide,
• a bayonet insert provided on a second instrument part to be coupled with said first instrument part, the bayonet insert having a stud end provided with spaced apart lugs which extend axially from and radially outwardly from the stud to engage the longitudinal slot upon axial displacement of the instrument parts relative each other, the lugs having end walls, and
• an interlock piece having a distal end and being resiliently biased toward the second instrument part upon its insertion in said bayonet guide of said bayonet sleeve for locking engagement with said stud end of said bayonet insert to prevent said bayonet insert from rotating, said distal end of the interlock piece having an axial recess defining a floor and two axially extending and radially spaced apart lugs which extend along the longitudinal axis and abut said lugs of the bayonet insert upon axial displacement of the instrument parts so as the interlock piece and the bayonet insert are displaced axially in a terminal end position, wherein the lugs of the bayonet insert are aligned with the transverse slot of said bayonet guide upon angularly displacing of the first and second instrument parts relative to one another to an inhibiting position, wherein said interlock piece is forced toward said bayonet sleeve until the end walls of the lugs of the bayonet insert contact the floor of the axial recess of the interlock piece, wherein the axial lugs of the bayonet insert and the interlock piece are axially engaged and come into inhibiting engagement to arrest relative angular displacement of the instrument parts, said interlock piece being moveable away from said bayonet sleeve to release said bayonet insert.