| 摘要 |
A cylindrical tire building former (11) has two sets of radially expandable segments (37) or (38) located one set at each axial end of the former. The sets of segments (37) or (38) are expanded by engagement of each segment with an axially moveable wedge member (36). The wedge member (36) may comprise an annular body, or an annular array of individual wedges. The wedge member (36) is moved by operation of a plurality of screw struts (47) which are arranged on a pitch circle and which are each rotated by a planet gear (51). The planet gears (51) are driven simultaneously by a central sun gear (52) to move the wedge member evenly along the screw struts (47). |
