Compact high-torque device for rotating pipe

摘要

There are first and second elongate casing sections (10,11) pivotally connected to each other at a pivot (12). First and second driven sprockets (19,20) are mounted, respectively, on the casing sections at locations remote from the pivot. A drive sprocket (17), mounted on the first casing section is driven by a motor-gear assembly (16). A continuous chain (18) is mounted around the drive sprocket, and around the driven sprockets, having an inverse internal portion adapted to receive and directly contact the tubular well element (13) to be rotated. Cylinders (14,15) are connected between the casing sections to pivot them toward and away from each other and thus alternately clamp the inverse internal portion around the well element, and release such element form the inverse internal portion.