US Patent 9187260 Conveying system and conveying method

A system for transporting an article between a plurality of processing devices includes a track extending above load ports of the processing devices, and an overhead travelling vehicle that travels along the track and has a hoist. A local track disposed lower than the track extends at least to a position under the track, and is oriented perpendicular to the track when viewed from above. A local carriage travels along the local track and has a hoist for vertically moving the article. A buffer disposed below the local track delivers and receives the article to and from the local carriage, and extends at least to a position under the track.