摘要 |
A lift actuator comprises a sun screw having a longitudinal axis and being restrained from rotation about the longitudinal axis of the sun screw, at least one planetary screw having a longitudinal axis and being in thread engagement with the sun screw, and a drive nut having a longitudinal axis coincident with the longitudinal axis of the sun screw and being in thread engagement with the planetary screw. The drive nut is mounted for rotation about the longitudinal axis of the drive nut but is restrained from translation along the longitudinal axis of the drive nut. When the drive nut is rotated by a rotational energy source, the drive nut drives the planetary screw to rotate and thereby translate axially relative to the drive nut, and the rotating planetary screw in turn causes the sun screw to translate axially relative to the rotating planetary screw.
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