METHOD AND DEVICE FOR SCREWING AND UNSCREWING THREADED PIPE CONNECTIONS Russian patent published in 2006 - IPC E21B19/16 

FIELD: mechanical engineering, particularly drilling string and casing pipe connection equipment.

SUBSTANCE: method involves stopping one pipe and rotating another pipe for screwing and unscrewing of above pipes with the use of hydraulic drive and braking system to transmit differently directed torques with the same data along with reactive moment reduction by drive and braking system. Device comprises two coaxial power tongs. Each power tong includes body and pipe squeezing mechanism. The power tongs have common drive including high-speed reducer and differential block kinematically connected one to another. Differential block comprises body with outer and inner toothed crowns, planet carrier with three satellites installed on the carrier, the first tong arranged in body, driven gear kinematically connected to planet carrier and the second tong installed in the body and adapted to cooperate with corresponding gears of pipe squeezing mechanisms. Pipe squeezing mechanism of the first tong is fixedly secured to braking pulley of braking system installed on the first tong body. The braking system comprises four pressing shoes and cylindrical case with hydraulic cylinder for shoe pressing arranged so that cylindrical case may rotate with pulley and pipe squeezing mechanism of the first tong relative pipe squeezing mechanism axis. The cylindrical case is additionally provided with two rests. One rest is fixedly connected with cylindrical case and cooperates with two hydraulic cylinders, which are adapted for thread tightening/unfastening. Another rest is connected with cylindrical case by hinged axis and also cooperates with two other hydraulic cylinders, adapted for thread tightening/unfastening, which provides elimination of reverse reaction and increase of pipe squeezing mechanism torque and locking moment.

EFFECT: possibility to use one drive provided with differential gear to perform screwing/unscrewing operations.

2 cl, 2 dwg