Rack and optical apparatus using the same

摘要

The rack includes a first member having a first tooth engaged with a lead screw, a second member having a second tooth engaged with the lead screw, a third member having a third tooth engageable with the lead screw, a first forcing unit configured to apply a force between the first and second members, a second forcing unit configured to apply a force between the first member and third members, and a limiter configured to limit a distance between the third tooth and the lead screw so that the third tooth is separated from the lead screw when the first and second teeth are engaged with the lead screw by the force applied by the first forcing unit and a distance between the first tooth and the third tooth is smaller than an outer diameter of the lead screw.

主权项

1. A rack attached to a movable member and configured to transmit a driving force of a driver to the movable member, the rack comprising:
a first member having a first tooth engaged with a lead screw rotated by the driver; a second member having a second tooth arranged opposite to the first tooth with respect to the lead screw and engaged with the lead screw; a third member having a third tooth arranged opposite to the first tooth with respect to the lead screw and engageable with the lead screw; a first forcing unit configured to apply a force between the first member and the second member so that the first tooth and the second tooth approach to each other; a second forcing unit configured to apply a force between the first member and the third member so that the first tooth and the third tooth approach to each other; and a limiter configured to limit a distance between the third tooth and the lead screw so that the third tooth is separated from the lead screw when the first tooth and the second tooth are engaged with the lead screw by the force applied by the first forcing unit and a distance between the first tooth and the third tooth is smaller than an outer diameter of the lead screw on a plane that passes the center axis of the lead screw and a contact position between the first tooth and the lead screw.