DRUM FOR PRODUCING A TYRE, PROVIDED WITH RETRACTABLE SECTORS

摘要

The drum (2) for producing a tyre blank comprises: - sectors (6v, 6c) forming a circumferential face of the drum, and - at least one cam (60) controlling a radial movement of the sectors relative to a rotational axis (12) of the drum. The cam has two main faces (66, 68) and is arranged such that a monotonous movement of the cam results first in the radial movement of some of the sectors (6v) owing to ramps (62) located on the first face (66) of same without modifying a radial position of the other sectors (6c), then results in the radial movement of the other sectors (6c) owing to ramps (64) located on the second face (68) of same, the movement of all the sectors (6v, 6c) then being simultaneous.