Lifter device

A lifter device comprising:

• a pinion gear configured to mesh with an input gear of a link mechanism for lifting and lowering a seat;
• a rotation control device configured to control rotation of the pinion gear, the rotation control device including:
• a rotation shaft configured to rotate in synchronization with the pinion gear;
• a support member supporting the rotation shaft such that the rotation shaft is rotatable;
• a rotation drive mechanism configured to rotate the rotation shaft in a lifting direction or a lowering direction of the seat in accordance with an operation direction of an operation handle when the operation handle is operated to lift or lower the seat, the operation handle being configured to lift and lower the seat;
• and
• a lock mechanism configured to allow rotation of the rotation shaft when the operation handle is operated to lift or lower the seat, and configured to lock the rotation of the rotation shaft when the operation handle is in an operation-released state, the lock mechanism including:
• a first tooth provided on one of the rotation shaft and the support member;
• and
• a second tooth provided on the other one of the rotation shaft and the support member, the second tooth being configured to selectively mesh with the first tooth to lock relative rotation of the rotation shaft and the support member;
• and
• a speed increasing mechanism provided closer to the rotation shaft than a meshing portion of the first tooth and the second tooth in a rotation transmission path, the speed increasing mechanism being configured to transmit the rotation of the rotation shaft to one of the first tooth and the second tooth and configured to speed up the transmitted rotation of the rotation shaft, the one of the first tooth and the second tooth being located closer to the rotation shaft than the other one of the first tooth and the second tooth in the rotation transmission path.