DEVICE FOR UNSCREWING PIPES IN WELL Russian patent published in 1999 - IPC

FIELD: oil and gas production industry. SUBSTANCE: device is used in repair of oil and gas wells. It has body, hollow shaft, reversing mechanism concentrically located inside body and connected with hollow shaft. Reversing mechanism is made in the form of driving gear, driven gear, and intermediate gear. Braking unit comprises stepped bush installed concentrically with respect to hollow shaft and adapted for free rotation relative to hollow shaft. Extendible socket anchors and socket piston holder are interconnected. Stepped bush at side of upper end has concentrically made bore with blind bottom. Located in bore is movably sliding socket piston holder, and located between socket piston holder and taper bush are extendible socket anchors adapted for free sliding along guide members of taper bush. Seated in internal bores of socket piston holder and extendible socket anchor is return spring. Made at side of lower end of stepped bush are coaxial and uniformly spread over circumference are internal holes or bores. Located in bored holes are intermediate gears with hubs which are adapted for free separate rotation in coaxial holes. Made in intermediate bored holes are radially located openings for ensuring contact between intermediate gears and driving gear and driven gear. Installed in lower part of device for possible interaction with lower part of driven gear is movable adapter for connection of catching tool. Application of aforesaid embodiment of device allows for improving reliability of fixing unit together with simplification of overall design. EFFECT: higher efficiency. 3 dwg