Portal crane is a variant of bridge crane, also known as gantry crane. Mainly used for loading and unloading operations of outdoor cargo yards, material yards, and bulk cargo. Portal cranes have the characteristics of high site utilization, large operating range, wide adaptability, and strong universality, and are widely used in port cargo yards.

Its metal structure is like a portal frame, with two legs installed under the main beam, which can walk directly on the ground track. The two ends of the main beam can have outward overhanging cantilever beams.

A gantry crane (also known as a gantry crane) is a bridge type crane supported on the ground track by two side legs. Structurally, it consists of a gantry, a large vehicle operating mechanism, a lifting trolley, and electrical components. Some gantry cranes only have legs on one side and operate on the other side of the factory or wharf, called semi gantry cranes. The upper bridge frame (including main beam and end beam), supporting legs, lower crossbeam and other parts of the gantry crane. In order to expand the operating range of the crane, the main beam can extend beyond the support legs to one or both sides, forming a cantilever. A crane trolley with an arm frame can also be used to expand the operating range of the crane through the pitch and rotation of the arm frame.