Patent ID: 7069817

Claim:
A power tong comprising: a frame; an outer ring rotatably supported on the frame and having a side opening through which pipe may pass to a central position in the tong; a releasable pipe-gripping mechanism comprising: (i) an inner ring; (ii) an active jaw mounted on said inner ring moveable radially with respect to said inner ring between an open position and a closed position and which has an arcuate-shaped pipe-gripping surface on the first end thereof and first and second camming surfaces on the opposite end thereof, said camming surfaces extending from opposite edges of said opposite end to an apex at the centerline extending from said first end of said active jaw to said opposite end thereof; and (iii) at least one side jaw mounted on said inner ring and pivotal between a closed position and an open position; means for rotating said outer ring with respect to said frame and said inner ring; rollers mounted on said outer ring rotatably supporting said inner ring coaxially on the outer ring with at least one of the rollers positioned to engage said first camming surface and move said active jaw toward a closed position when said outer ring is rotated in a first direction, at least one roller positioned to engage said second camming surface when said outer ring is rotated in the opposite direction, and at least one roller positioned to engage said side jaw and pivot said side jaw toward a closed position when said outer ring is rotated with respect to said inner ring; and means for limiting relative rotational movement of said inner ring with respect to said outer ring, wherein said means for limiting relative rotational movement of said inner ring with respect to said outer ring comprises: a member secured to and rotatable with said outer ring having an elongated arcuate aperture therein, the length of said arcuate aperture defining the limits of desired rotational movement of said outer ring with respect to said inner ring; and a limit pin secured to said inner ring and projecting into said elongated arcuate aperture.