Crane: Crane (English: Crane) refers to the machinery that hangs heavy objects with hooks or other fetching devices and performs cyclic operations such as lifting and moving in space. There are many kinds of cranes, such as "crane", "tower crane", "crown block" and "traveling crane". Usually refers to one or several types of cranes. According to the structure, it can be divided into three categories: bridge crane, cable crane and jib crane. According to the fetching device, it can be divided into fifteen categories, such as hook crane, grab crane and electromagnetic crane. According to the mobile mode, it can be divided into five categories: fixed crane, climbing crane, mobile crane, jib crane and walking crane. According to the driving mode, it can be divided into three categories: manual crane, electric crane and hydraulic crane. There are also classified by slewing ability, support mode and operation mode.