| 摘要 |
An annular expanding ring structure comprising a number of circumferentially arranged segments adapted to undergo partly radial movements relative to the central axis there-through. The segments are arranged in two complementary sets such that each of the segments in the ring structure is interposed with surface contact between the two adjacent segments of the other set in alternating fashion. Each of the segments is suspended in a cylindrical body constituting the support for the segments to be moveable in synchronized fashion along a straight axis lying in the respective one of two identical cones, one for each set. The cones have common axis and geometrically coinciding base circles, which circle constitutes the center plane of the ring structure. Each of the segments has two opposed plane sliding faces, and the average angle between the opposed side faces of each segment viewed in a plane normal to the central axis is 360 DEG : E, wherein E is the total number of segments. |
