Four-link Portal Crane

​The four-link portal crane is a slewing boom crane with a gantry structure, which has four working mechanisms: hoisting, slewing, luffing, and traveling. It is mainly used in ports, docks, shipyards, hydropower stations and other places for loading and unloading, transferring, assembling and installing of goods. It has the advantages of large clearance height, low overall crane height, horizontal movement of the load during the luffing process, and constant lifting capacity regardless of the outreach. It can be adapted to different cargo forms according to different attachments, such as hooks, grabs, electromagnets and so on. However, this type of crane also has the disadvantages of complex structure, heavy weight, complicated mechanism arrangement and difficult maintenance operation. And its working speed is low, can not meet the requirements of high efficiency.