Low-clearance rotary drilling rig of special elevator

The invention discloses a low-clearance rotary drilling rig of a special elevator and belongs to the technical field of rotary drilling rigs. The low-clearance rotary drilling rig is characterized inthat a mast is fixedly mounted on the right side of an upper car; a drilling rod is slidably connected with right side of the mast; a drilling tool is fixedly mounted at the lower end of the drillingrod; a pulley seat is fixedly connected with the surface of the mast; a steel wire rope is in contact connection with the interior of the pulley seat; the pulley seat comprises a baseplate; a left supporting plate and a right supporting plate which are symmetric to each other are fixedly connected with the upper end of the baseplate; a sleeve hole is formed in the side surface of the left supporting plate; and a left bearing is fixedly connected into the sleeve ring in a sleeving manner. The low-clearance rotary drilling rig is equipped with a roller which has the automatic extrusion, shock absorption and force relief