Controllable cantilever crane

The invention relates to the technical field of lifting devices, aims to solve the problems that in the prior art, equipment arrangement is compact, space is narrow, the lifting appliance dismounting and mounting risk is high, equipment transfer is inconvenient, the stability and safety of lifted objects are affected, and potential safety hazards of human bodies and equipment are large, and provides a controllable cantilever crane which comprises a main suspension arm. One end of the main suspension arm is hinged between the first mounting seat and the second mounting seat; the other end of the main lifting arm is rotatably connected with an auxiliary lifting arm, and the axial direction of the main lifting arm is parallel to the axial direction of the auxiliary lifting arm; slidable chain block groups are connected to two sides of the auxiliary lifting arm; a main suspension arm transmission mechanism for controlling the rotation angle of the main suspension arm and a main suspension arm locking device for l