Drum half, tire building machine and method for operating said tire building machine

A first drum half for together with a second drum half forming a tire building drum of a tire building machine, wherein the tire building machine comprises a rotation axis (X) and a drum shaft extending along the rotation axis (X) for supporting said first drum half and said second drum half on opposite sides of a center (M) of the tire building drum, wherein the tire building machine further comprises a first drive member and a second drive member movable in an axial direction (A) parallel to the rotation axis (X) with respect to the first drum half, wherein the first drum half comprises:

• a base for mounting the first drum half to the drum shaft, wherein the base has a central axis (X) that is arranged to coincide with the rotation axis (X), wherein the base is arranged to be movable over the drum shaft in the axial direction (A) parallel to said central axis (X);
• and
• a crown-up section comprising a plurality of crown segments distributed circumferentially about said central axis (X) and movable with respect to the base in a crown-up direction (C) outwards in a radial direction (R) with respect to the central axis (X) from a crown-down position towards a crown-up position;
• wherein the first drum half comprises a displacement member that is movable in a crown drive direction (T) parallel to the axial direction (A) for displacing the crown segments in the crown-up direction (C), wherein the first drum half further comprises a first coupling member for coupling the first drive member to the base to drive the movement of the base in the axial direction (A) and a second coupling member for coupling the second drive member to the displacement member to drive the displacement of the crown segments in the crown-up direction (C),
• wherein the crown-up section (5) comprises a crown support (51) for supporting the crown segments (50) with respect to the base (2) and a crown drive (52) for displacing the crown segments (50) with respect to the crown support (51), wherein the displacement member (15) is arranged for driving the crown drive (52) in the crown drive direction (T) and wherein the crown drive (52) is arranged for converting the movement of the displacement member (15) in the crown drive direction (T) into the displacement of the crown segments (50) in the crown-up direction (C),
• wherein the first drum half (11) comprises a locking member (60) that is arranged for locking the crown drive (52) in the axial direction (A) with respect to the base (2),
• wherein the displacement member (15) is arranged to be movable in the axial direction (A) with respect to the locked crown drive (52),
• wherein the first drum half (11) is further provided with a turn-up section (4) comprising a plurality of turn-up arms (40) distributed circumferentially about said central axis (X) and an arm support (41) for supporting said turn-up arms (40) with respect to the base (2), wherein the arm support (41) is movable in an arm drive direction (D) opposite to the crown drive direction (T), wherein the turn-up arms (40) are rotatable with respect to the arm support (41) from an arms-down position towards an arms-up position in response to the movement of the arm support (41) in the arm drive direction (D), wherein the displacement member (15) is movable in the arm drive direction (D) with respect to the locked crown-drive (52) for displacing the arm support (41) in said arm drive direction (D).