Patent ID: 7861619

Claim:
A power tong construction, in particular designed to annul compulsory forces that may arise within the tong construction during makeup/breakout operations of pipe joints in a string of pipes, which power tong is constructed as a unit having a main frame carrying a torque tong and a backup tong, which main frame is normally located on a drill floor on board a floating vessel or on a fixed installation, and is translatory arranged in guide rails on the drill floor, and the torque tong is loosely suspended and â€œfloatinglyâ€ arranged in the power tong construction, said power tong thereby having a limited freedom of motion in all directions in the horizontal plane and vertical plane, and means to counteract external rotation and annulment of compulsory forces comprising at least a pair of working cylinders articulated secured in each end to the torque tong and the main frame respectively, and the working cylinders are in fluid communication with each other via cross-connected pipe connections, characterized in that each working cylinder comprises an internal piston having equal area on both sides and a through running piston rod.