260 on the bowden tube side part 2 and 330 370 of the locking element 3 as shown in fig1 which adjoin one another at the conclusion of the setting movement of the part 2 on the bowden tube side and thus secure the locking position of the locking element 3 opposite the detent elements 30 of the locking element 3 are the detent elements 13a of the part 1 on the housing side which extend along the displacement direction arrow of the part 2 on the bowden side as shown in fig2 b saw tooth like detent elements have the advantage that their inclined flanks 37 easily slide on one another during a cable length compensating displacement movement and necessitate the release of the keyed engagement lock whilst the radially aligned flanks with rear cut sections 38 see fig1 prevent a resetting movement of the part on the bowden tube side beyond the reserved play in the event of strain in the locking direction saw tooth like detent elements with rear cut section 38 perpendicular to the locking direction have a self strengthening effect which secures the positive lock and thus the locking action when using a markedly defined rear cut section 38.