Expandable mandrel having adjustable width

A rotatable drum useful in the manufacture of vehicle tires and having a main shaft defining a rotational axis of the drum comprising

• a plurality of segments collectively defining the outer circumferential surface of the drum, said segments being divided into first and second sets of segments, one set of segments being disposed on each of the opposite sides of the transverse center plane of the drum,
• a central control mechanism controlling the radial positions of all the segments simultaneously and equidistantly from the rotational axis of the drum, while permitting axial movement of the two sets of segments relative to one another while the segments are positioned at any given radial location of the segments, said central mechanism including means interconnecting said segments of said sets of segments for movement of the plurality of segments of each of the two sets of segments radially of the rotational axis of the drum as slaves of the central mechanism, whereby said segments are selectively positionable between expanded positions radially of the rotational axis of the drum to provide a substantially continuous circumferential outer surface of the drum for the layup of a tire carcass thereon, and collapsed positions radially of the drum to permit the removal of a formed toroidal carcass from the drum,
• means mounting said segments of each set of segments for selective positioning thereof axially of the drum from a location external of the drum to adjust the overall working width of the drum, said means including multiple lead screws associated with the main shaft of the drum and actuatable simultaneously from a single location external of the drum to effect adjustment of the width of the drum, with disengagement of the lead screws from the external source of their adjustment once the width of the drum is selectively established, thereby ensuring locking of the drum width against unintended change thereof.