A nut stacking mechanism (-1-) for the displacement of slats between a stacking zone (L2) and a sliding zone (L1), comprising a spindle (2), on which a nut (3) is displaceable between the stacking zone (L2) and the sliding zone (L1), a rotation stop element (4), to form in the sliding zone (L1), in the rotational direction of the spindle (2), an obstacle for the movement of the nut (3), and a stacking element (5), to form in the stacking zone (L2), in the longitudinal direction of the spindle (2), an obstacle for the movement of the nut (3), wherein, by displacement of at least a part of the rotation stop element (4) and the stacking element (5), the boundary between the stacking zone (L2) and the sliding zone (L1) is provided displaceably in the longitudinal direction of the spindle (2).