DRILL PIPE ROTARY HEAD OF DRILLING RIGS Russian patent published in 1994 - IPC

FIELD: drilling rigs. SUBSTANCE: rotary head has sleeve with splined bore in its upper part conjugated with gear wheel in middle part to receive swivel stem, and in its lower part, ears with arched clamps articulated in them. Outer surfaces of arched clamps are conjugated with planes of segment located in suspended holder which encloses sleeve. Sleeve outer side has annular recesses to receive heads of retainers built in body of suspended holder. Arched clamps have hinge members to receive changeable levers with working retaining blocks. EFFECT: higher efficiency. 4 cl, 4 dwg