Abstract: A circulating latch transport mechanism is provided which is capable of moving freely in any direction across the under side of a horizontal array of parallel I-beams while remaining attached to this array. The transport mechanism is attached simultaneously to several I-beams, which allows the mechanism to move across a ceiling in a longitudinal direction with respect to the I-beams, a direction perpendicular or transverse to the I-beams, and, by the mechanical independent actions of the longitudinal and perpendicular motions, in an arbitrary direction.