| 摘要 |
Second arm sections (54a, 54b) formed as inner peripheral cylindrical surfaces that have, as the central axis, an axis line that is parallel to the axis of rotation of shaft member (50a, 50b), support first arm sections (44a, 44b) such that the spherical centers (P1a, P1b) of outer peripheral spherical sections (45a, 45b) that are attached to the first arm sections (44a, 44b) are bound to the central axis line of the second arm sections (54a, 54b). |
