Drum and method for manufacturing a tire blank

A drum for manufacturing a tire blank, the drum comprising a shaft extending axially, two flanges movable in axial translation along the shaft, and means for supplying compressed air, each flange comprising at least one pneumatic effector cooperating with the tire blank, and at least one flange comprising a first radially internal ring movable in axial translation along the shaft, and a second radially external ring comprising the at least one pneumatic effector, wherein the second radially external ring is movable in rotation around the first radially internal ring by means of at least two airtight pivot connections, the first radially internal ring, second radially external ring and the pivot connections delimiting at least one sealed chamber, and wherein the at least one flange comprises at least one first compressed-air circulation channel, a first section of the first compressed-air circulation channel belonging to the first radially internal ring being connected at one of its ends to the compressed-air supply means and at the other of its ends to the sealed chamber, and a second section of the first compressed-air circulation channel belonging to the second radially external ring being connected at one of its ends to the sealed chamber and at the other of its ends to the at least one pneumatic effector.