QW2 Derrick crane is used at the roof of building for dismantling inner-climbing tower crane. It is specially designed for small high-rise building with reasonable layout and good appearance. Its installation and slewing space is smaller than general crane. Its lifting mechanism, slewing mechanism and radius changing mechanism adopt frequency control of motor speed and its complete safety devices to ensure stable, reliable and high efficient work. Its max. lifting weight is 2ton, max. lifting height is9.8m, Lifting level distance is 9.8m, Lifting angle of lifting arm is 20-70 o