FIELD: oil producing industry. SUBSTANCE: brake mechanism to control energy release of drill rod string is designed for use in oil well rotary pump. Rotary pump has rotating element arranged in energy line from main motor to upper end of drill rod string. It should rotate at constant ratio and direction relative to upper end of drill rod string. Rotating element sets flowing medium pump into operation by means of overrunning clutch so that when upper end of drill rod string rotates in normal direction, clutch slips and does not sets pump into working. But when upper end of drill rod string tries to turn in opposite direction, for instance, at stopping or interruption of energy supply, pump is set into operation to delivery flowing medium from reservoir and to reservoir along closed line which includes also flowing medium flow limiter. EFFECT: simplified design, improved reliability. 11 cl, 2 dwg
