主权项 |
1. A coupling assembly for connecting and centralizing a threaded-end member and a box coupling, the coupling assembly comprising:
a mandrel having a rotor receiving surface, the mandrel having a first threaded end and a second threaded end, the first threaded end for connecting to the threaded-end member; the second threaded end having a first threaded portion for connecting to the box coupling and a second threaded portion for receiving a nut, the second threaded portion located between the first threaded portion and the rotor receiving surface; a stop formed on the mandrel between the first threaded end and the rotor receiving surface; the first threaded portion having a first thread pitch and the second threaded portion having a second thread pitch, the first thread pitch being different from the second thread pitch and the first threaded portion being narrower in diameter than the second threaded portion; a nut threaded onto the second threaded portion; and a rotor with raised fins, the rotor being mounted on the rotor receiving surface between the nut and the stop and being movable axially on the rotor receiving surface. |