HIGH-TORQUE PIPE TONGS Russian patent published in 1994 - IPC

FIELD: drilling equipment. SUBSTANCE: pipe tongs consist of bearing frame 1, power swivel head 2, stop tongs 3, hoisting carriage 4, making and breaking power cylinders 5, carriage lifting power cylinder 6, wheels 7, wheel chain drive 8. Power swivel head includes side parts, rotor wheel, jaw holder parts, clamping shoes, shoe release springs, support rollers, dies, hydraulic motors, push forks, clamping power cylinders, slides, friction plates, springs, coupling pin, alignment indicator with axle, retainer, projection, retainer socket, pins for opening side parts, collar body. Carriage has adjustable rollers. Stop tongs are provided with clamping power cylinders. Pipes are clamped at their locking part 19. For releasing rotor gear of swivel head from bulging-out forces, provision is made for preliminary forcing of clamping shoe dies into pipe body with the aid of clamping power cylinders, positioned in tongs housing, with subsequent retention of clamping shoes with the use of steep (from 15 to 36 deg) master cams in rotor wheel. EFFECT: improved reliability. 2 cl, 8 dwg