fs5513 tower crane hoisting device it adopts electromagnetic clutch to control speed and its operation is easy and convenient. it adopts vortex braking motor to reach ideal lifting speed and slow inposition of loading. slewing gear it adopts hydraulic coupler for transmission.its work si steady and reliable. when it rotates,there si no shaking or swing. it can rotates with wind. trolley device it adopts electromagnetic disk type brake. its running speed is high. its running is steady and reliable. standard structure the surface of the steel material is pre-treated. the removal of gravitation is treated. it adopts large plasma cutting. it adopts auto melding. electric elements the electeical equipment adopts central contel.it can automatically detect trobles,such as hitting by mistaken operation,overloading and surpass scale work,and send corresponding alarm of sound and lighe. it adopts schneider product. its overloading capactiy is strong and its steadiness is good. jack-up device it adopts outer side hydraulic jack-up. its safety is higher. its lifting and falling is convenient and smooth