The rotary drilling rig jack is also called a swivel joint. One end is connected to the wire rope and the other end is connected to the drill pipe.When the drill pipe rotates, the lower end of the lifter rotates synchronously with the drill pipe, and the upper end of the lifter remains stationary, thereby eliminating the torque brought to the wire rope when the drill pipe rotates and protecting the wire rope from damage due to selective torsion.The lifter needs to be maintained regularly, add fresh grease, and remove contaminated grease to ensure that the lifter rotates flexibly and prolongs its service life.