HYDROMECHANICAL DEVICE FOR RELEASING OF STUCK PIPES Russian patent published in 1995 - IPC

FIELD: well drilling. SUBSTANCE: hydromechanical device for releasing of stuck pipes has body 1, separating tube, 2, rod 3 on which sub is screwed and connected with cylinder 5. Body has safety valve including locknut 7, spring 8 and ball 9. Extending support of device includes control fork 10 rigidly connected with thrust bearing 11 installed in slots of segment holder 12 interacting with segments 13 and 14. In lower part, separating tube 2 interacts with movable sub 15 moving in cylinder 16 and is rigidly connected with piston 17. Piston has thread on its end to connect fishing tool 18. Axial displacements of fork 10 and segments 13 and 14 are limited by shoulder 19 on separating tube and by pin 20 locking the position of segment holder 12. EFFECT: higher efficiency. 2 cl, 3 dwg