20110265999 | REVERSE TORQUE DRIVE SYSTEM - A reverse torque drive system for a wellhead has a hydraulic pump having an inlet and an outlet, and a hydraulic motor having a first port and a second port. There is a valve body having a first position that connects the outlet of the hydraulic motor to the first port and the second port to the inlet, and a second position that connects the outlet to the second port and the first port to the inlet. One or more sensors are connected to measure a condition, and a controller moves the valve body from the first position to the second position upon the sensor sensing a predetermined condition. | 11-03-2011 |