A stent or stent-graft delivery system includes a handle having a graft cover retractor having a screw gear and a drive and quick release assembly. The drive and quick release assembly allows a user to retract a graft cover by rotating the assembly in a first rotational direction about the screw gear. When the assembly is being rotated in a particular rotational direction, a partial revolution in the opposite rotational direction disengages the assembly from the screw gear, which is sensed by a change in the force required to rotate the assembly. With the assembly disengaged from the screw gear, the assembly can be slid along the screw so that the graft cover can be positioned more quickly. In transitioning from using the screw gear to sliding along screw gear, it unnecessary to push any button and unnecessary for the user to remove her/his hand from the assembly.
