ROTARY GEAR ASSEMBLY FOR POWER TONGS

摘要

A rotary gear assembly for a power tong used to make up and break out threaded connections between longitudinally adjoined pipe sections includes an outer gear ring having gear teeth around an outer periphery for receiving drive power to rotate the gea r ring about a central axis, an inner ring slidingly fittable coaxially within the gear ring, a nd means for rotationally engaging the outer gear ring with the inner ring such that both rin gs rotate together following limited clockwise or counterclockwise rotational movement of the outer gear ring relative to the inner ring about the central axis. The inner ring incl udes an inner face for providing a camming surface for pipe gripping means of the tong, and a front al mouth alignable with a corresponding frontal mouth of the outer gear ring to provide a n opening for permitting an elongated pipe section to be axially positioned within the rings. The outer gear ring is rotatable with respect to the inner ring about the central axis to open and close the opening.