STATIONARY WRENCH FOR DRILLING EQUIPMENT Russian patent published in 1996 - IPC

FIELD: screwing and unscrewing of threaded connections of drilling tubes and casings. SUBSTANCE: wrench has locking mechanism with carriage mounted on power column, screwing-unscrewing mechanism connected with stabilizing locking mechanism, which has power cylinders with stabilizing moment relative to screwing center. Power cylinders are positioned at different sides with respect to longitudinal diametric plane of tube clamping part of wrench. Wrench is further provided with oscillating telescopic support having device responsive to torque variations, auxiliary hydraulic cylinder mounted on oscillating telescopic support and cantilevered fingers rigidly fixed on screwing-unscrewing mechanism. Power cylinders are formed as spring-loaded casings with immovable plungers. Device responsive to torque variations is formed as double-sided dynamometer-type detector engageable with cantilevered fingers. Screwing- unscrewing mechanism is balanced with respect to its own center of weight by power cylinder casing springs and with respect to screwing center by working agent pressure in power cylinder cavities. Supporting surfaces of cantilevered fingers are made spherical. Power cylinders are positioned within tube clamping part of wrench. EFFECT: reduced wear of threaded connections by compensating lateral and angular shears of tubes to be screwed, improved maintenance and increased safety of work. 3 cl, 5 dwg