Abstract: An open-throat power tong for making up or breaking apart an oilfield tubular connection, includes a cage plate lock system. The lock system connected to each cage plate extends across the space provided by the open throat in the cage plate when locked in the closed position. This provides support for the cage plates, resisting their tendency for expansion. The cage plates are mounted on the ring gear for rotation about a common center. The support provided to the cage plates for resisting expansion is communicated to the ring gear, thus providing support to the ring gear against expansion.