Ceiling carrier vehicle

1. An overhead transport vehicle comprising:

a traveler to travel along a traveling rail;

an elevator provided to the traveler;

a holder to be raised and lowered by the elevator and to hold a flange included in a container;

a positioner to ascend and descend with respect to the holder and to engage with a recess formed in the flange;

a detector to detect a relative ascending operation of the positioner with respect to the holder;

a controller to recognize that the container is disposed on a mounting surface of a transfer destination when the detector detects the ascending operation in a case where the holder is lowered by the elevator; and

a dog to ascend and descend in association with ascending and descending operations of the positioner with respect to the holder; wherein

the detector detects a position of the dog;

the dog includes a first screen including a first upper end and a first lower end, and a second screen including a second upper end and a second lower end;

the detector includes a first photo interrupter to detect a position of the first screen, and a second photo interrupter to detect a position of the second screen;

the first lower end and the second upper end are positioned at a same height; and

an optical axis of the first photo interrupter and an optical axis of the second photo interrupter are positioned at a same height.

2. The overhead transport vehicle according to claim 1 , wherein the controller recognizes that the holder reaches a holding position when the detector detects an ascending operation in a case where the holder is lowered by the elevator.