Tensioning apparatus for tie down lines

摘要

A measured and controlled tension is applied to one or more lines or cables attached to a drilling rig. Preferably, the tensioned line provide reactive torque support for the power swivel, The controlled tension allows a greater power swivel torque to be used on existing drilling rig structures and better distributes any portion of the torque load reacted by the structure. The controlled tension system can also be integrated into a fail-safe control system, where sensed cable failure or excessive cable loads cause a safe shutdown of operations, or the measured tension may also be based to control other drilling operations, such as hoisting speeds.