Structure: stationary , stationary and revolve ,moving and revolve; Cross-section of boom and column is calculated scientifically. Drooping of boom along horizontal travel is 2mm/m; Boom lifting device has the anti-falling device, of ratchet structure, safe and reliable; Boom end has cross-slides, which can be controlled thru manual pendant; Control roller has eccentric shaft,which can decrease clearance between roller and rail; Column revolve unit has motor-driven and manual drive; Control unit includes control board and pendant ,interface with positioner and turning rolls also prepared.