Labor-saving device for pin penetrating and disengaging of movable pulley of crane

The utility model discloses a labor-saving pin penetrating and disengaging device for a movable pulley of a crane. The labor-saving pin penetrating and disengaging device comprises an operation disc, a reduction gear set, a machine shell, a torque transmission rod and a worm, the operation disc is composed of a disc body and a transverse rod. The other end of the transverse rod is arranged at the upper part of the shell through a bearing; the torque transmission rod is installed in the middle of the machine shell through a bearing. One end of the worm is installed on the lower portion of the machine shell through a bearing. The reduction gear set is installed in the machine shell and comprises a small gear I, a large gear I, a small gear II and a large gear II. The pinion I is fixedly mounted on a cross rod of the operation disc; the large gear I and the small gear II are fixedly installed on the torque transmission rod. The large gear II is fixedly mounted on the worm; the small gear I is meshed with the lar