Tire building drum and a method for shaping tire components on said tire building drum

A tire building drum comprising a rotational axis that defines an axial direction of the tire building drum, wherein the tire building drum further comprises a bead holder extending in a circumferential direction around the rotational axis at a first axial position for holding a bead at said first axial position and an axially movable arm drive member extending circumferentially around the rotational axis at a second axial position spaced apart from the first axial position, wherein the tire building drum is provided with turn-up arms which are distributed circumferentially about the rotational axis for supporting tire components between the first axial position and the second axial position, wherein each one of the turn-up arms extends in a longitudinal direction from the arm drive member towards the bead holder and is hingably coupled to the arm drive member about a respective turn-up axis for turning up the tire components supported thereon around the bead at the bead holder as the arm drive member moves towards the bead holder, wherein the turn-up arms are hingable with respect to their respective hinge axes between a level orientation, in which the turn-up arms extend parallel to the axial direction, and a turned-up orientation, in which the turn-up arms extend under an oblique angle with respect to the axial direction from a first radius at the arm drive member towards a second, larger radius radially outside the bead holder, wherein the tire building drum comprises cover plates extending in the circumferential direction between each pair of directly adjacent turn-up arms to close gaps between the turn-up arms in the circumferential direction, wherein the cover plates are arranged to remain at the first radius when the turn-up arms are moved from the level orientation towards the turned-up orientation.