The kelly is used to transmit rotary motion from the rotary table or kelly bushing to the drillstring, while allowing the drillstring to be lowered or raised during rotation.
方钻杆用于传递转盘或者方钻杆补心的旋转运动到钻柱上去，并允许钻柱在上提或下放的过程中旋转。
2
Single-screw pump is a new volume of the inner rotary gear pump. The main working parts are eccentric screw (rotor) and fixed bushing (stator).
单螺杆泵是一种新型的内啮合回转式容积泵。主要工作部件是偏心螺杆（转子）和固定的衬套（定子）。
3
The utility model relates to a square bushing for measuring the torsion of a rotary table in the process of drilling Wells, which belongs to an appliance of well drilling equipment.