Ship unloader is the initial equipment for a bulk material unloading port. The shipunloader is mainly composed of grab ship unloader, continuous bucket wheel shipunloader, chain bucket unloader, screw shipunloader. Currently, grab shipunloader is the type most common applied mainly at coal or ore port. The composition mainly includes main body tower frame, travelling equipment, luffing equipment, cantilever beam, travelling trolley, unloading belt conveyor, grab lifting, grab switching mechanism, discharging bucket, etc. Generally, the capacity of grab shipunloader is 500t/h-1250t/h. The self weight of equipment is large, the self weight could reach 1200t-1500t for the grab shipunloader with large size and capacity of 1250t/h