Adjustment device for a top bow for a foldable roof

The device (6) has an actuator slide (17) enabling vertical lifting of a roof cover (5) and movement of the cover along a guide rail. The slide is movable along the guide rail and coupled with a front guide (25) by an actuator (20) that is engaged in a link of the guide. Locking hooks (28) of the guide moves out from a recess (29) of a front guide rail (8) during vertical lifting of the cover, where the cover points in a traveling direction (2) with its front edge (46) when a collapsible roof is opened. The slide is moved over a tension cable in or opposite to the traveling direction.