Overhead storage system

An overhead storage system comprising:

• an overhead transport vehicle including a traveling unit configured to travel on a rail arranged at least partially in a grid pattern and a body section suspended from the traveling unit and configured to hold an article below the rail;
• a storage rack disposed below the rail and configured to store the article;
• and
• a control unit configured to control operation of the overhead transport vehicle, wherein
• the body section includes a transfer device adapted to transfer the article to and from the storage rack, and
• in the storage rack, a plurality of article placement areas on which the article is adapted to be placed by the transfer device are set in a storage area corresponding to each of cells forming a matrix in the grid pattern of the rail;
• wherein
• the article includes a container body and a lid provided on a side of the container body,
• the article with the lid facing outside of the storage area is adapted to be placed in each of the article placement areas in the storage rack,
• the transfer device includes:
• an article holding unit configured to suspend and hold the article by gripping the article:
• a lifting drive unit configured to raise and lower the article holding unit;
• and
• a look-down sensor provided to the lifting drive unit and disposed, on a side opposite to a side closer to the lid, at a predetermined length apart from the article held by the article holding unit when viewed from above and configured to output a detection wave downward.