| 摘要 |
A lumbar support includes a seat back body, a lumbar plate, and plate moving means for moving the lumbar plate back and forth. The plate moving means includes a base portion supported by the seat back body and having a pair of oblong holes, a screw rod supported for free rotation on the base portion and having a male screw on its outer surface, a nut member having a centrally formed female screw threadedly engaged with the male screw, the nut member being moved axially of the screw rod by turning the latter, an anchor member connecting the lumbar plate to the nut member and having a ring-shaped pivot portion at an end thereof on the side of the nut member, and a distance compensating pin passed through the ring-shaped pivot portion and supported at the oblong holes so as to be movable in the longitudinal direction of the oblong holes. When the nut member is moved axially of the screw rod, the distance compensating pin moves longitudinally of the oblong holes so as to compensate for a change in distance between the center of the ring-shaped pivot portions and the center of rotation of the screw rod.
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