Variable counterweight structure suitable for movable arm tower crane

The utility model relates to the field of building tower crane counterweight, and provides a variable counterweight structure suitable for a movable arm tower crane, which comprises a balance arm, a connecting frame, a cargo boom, a counterweight module and a driving device, the cargo boom is hinged with the connecting frame, the balance arm is fixed on one side of the connecting frame, an inclined plane is arranged on the balance arm, and the counterweight module is arranged on the inclined plane. The balance weight module is installed on the inclined face of the balance arm, one end of the driving device is hinged to the connecting frame, the other end of the driving device is hinged to the cargo boom, and the balance weight module can drive the rope to pull the balance weight to move to the corresponding position according to the swing angle of the cargo boom. And due to the design of the inclined plane, when the cargo boom is reset, the counterweight module can return to the initial position due to the gr