Expansible build up drum for tyres and tyre breaker belts - has movable central segments, cylindrical springs in an elastic envelope

摘要

Drum comprises central segments fastened on levers which are displaced by an opening mechanism; cylindrical springs fastened at the segments, and an elastic envelope covering the springs. The springs are shaped as a bellows whose elements are distributed over the width of the bearing surface of the segments of the drum, and have lateral sections whose shape corresponds with the profile of the type to be built up. The elements of the spring embrace the expansible segments and are, in addn., bearing on elastic stringers whose one end is connected with a given segment whilst the other end slides freely over the adjacent segment as the drum is being expanded. Drum construction prevents deformation of the tyre to be built-up.