gantry crane gantry structure is divided according to the form

According to the structure of the door frame in the form of
(A) full gantry crane: the main beam without overhang, the car performed in the main span.
(B) semi-gantry cranes: leg height difference, according to the civil use of space requirements.
(C) double cantilever hoist crane: The most common type of structure, the effective use of its force structure and site area is reasonable.
(D) single cantilever gantry crane: This form of structure is often due to space limitations and be selected.