Patent ID: 7762160

Claim:
A power tong for rotating a pipe to make up or break up a threaded joint, comprising: a) a tong body having a center point and a tong body open throat; b) a ring gear rotatably supported by the tong body and having a ring gear open throat formed therein, the ring gear being positionable about the center point for alignment of the ring gear open throat with the tong body open throat; c) twin cage plates rotationally mounted with respect to the ring gear on opposite sides of the ring gear, the cage plates each having a cage plate open throat formed therein that is positionable for alignment with the tong body open throat, said cage plates being free to rotate with respect to the ring gear about the center point, but being constrained to maintain a center of rotation substantially corresponding to the center point ; and d) a cage plate locking means connected to an outer surface of each cage plate adjacent a side of the respective cage plate open throat therein, such cage plate locking means being positionable to extend from one side of the open throat of the cage plate across to the other side of the open throat of the cage plate for restraining the open throat of the cage plate from expansion, thus providing resistance to expansion of the ring gear when the power tong is engaging a pipe.