Foundry bridge crane is the main lifting and transportation equipment in the smelting workshop of the steel plant, which is used for the transfer, pouring and mixing of molten iron during the smelting process. Below 125t is generally YZ type double girder structure. Above 125t is generally YZS type four-beam structure. The YZS type adopts the structure of main and auxiliary double trolleys, four girders and four rails. It is mainly composed of bridge frame, main trolley, auxiliary trolley, hook beam, trolley operation and electrical parts. The inner sub-beam rail runs on the inner side, and the pick-up device of the main trolley is a hook beam with a fixed distance.