Patent ID: 8171971

Claim:
A driving apparatus for a tire building drum in which a drum main body is configured to expand or contract by a plurality of segments which are divided in a circumferential direction and a central shaft portion is made up of a cylindrical outer shaft and a threaded shaft provided inside thereof, comprising: a cylindrical outer shaft which is coupled to the outer shaft of the building drum; an inner shaft coupled to the threaded shaft; first rotational driving means coupled to the outer shaft for rotating the drum; and second rotational driving means coupled to the inner shaft via a clutch in such a manner as to be engaged with and disengaged from the inner shaft for expanding or contracting the drum, characterized in that: the first rotational driving means and the second rotational driving means comprise motors, respectively, which are driven to rotate by signals from a control unit, the motor which acts as the second rotational driving means being made to rotate forwards and backwards by signals from the control unit which indicate rotational directions, and by switching the clutch, when the drum is rotated through operation of the first rotational driving means, the second rotational driving means is held out of engagement with the inner shaft, while when the drum is expanded or contracted, the second rotational driving means is held in engagement with the inner shaft.