PIPE ROTATING DEVICE OF DRILLING TONGS Russian patent published in 1995 - IPC

FIELD: well drilling. SUBSTANCE: pipe turning device has pipe catching mechanism in form of outer and inner rings with articulated levers and switch of its rotation speed, friction brake with drive unit for reversing turning of inner ring relative to outer ring. Inner ring has spring-loaded retainers. Outer ring has inner grooves. Reversing unit is made in form of several stops. Friction brake has means for producing brake torque of two values. Stops are located in inner grooves of outer ring for motion over circle within groove interaction with spring-loaded retainers. Operating force of spring-loaded retainers is higher than that produced by stops at lower brake torque, and less than the force developed by stops at higher brake torque. Closed body of pipe rotating device is made with friction linings and drive. Means for producing brake torque of two values is made in form of flat brake disk installed on inner ring between friction linings for interaction with them and transmission of rotary torque. Drive of friction linings is made in form of spring-loaded pistons. EFFECT: higher efficiency. 2 cl, 3 dwg