DRILL ROD RELEASING DEVICE Russian patent published in 2006 - IPC E21B17/43 

FIELD: mining, particularly for well drilling with the use of anticrash device for coring equipment.

SUBSTANCE: releasing device connected with rotatable drill pipe comprises body, engagement member fixedly secured to the body, sub and shaft with left-handed coarse thread fixed to the body by means of fixing members. The sub is secured to rotatable drill pipe and to shaft through left-handed coarse thread. Engagement member is made as engaging clutch provided with extension formed on lower end thereof and with segments located on upper clutch end. The sub has a number of segments arranged in area of engaging clutch cooperation with sub. The segments are spaced apart to provide engaging clutch insertion in gaps between the segments. Slots adapted to receive segments formed on upper engaging clutch end are created on widened shaft section.

EFFECT: increased strength and reliability, prevention of spontaneous rotatable drill pipe rods turning.

3 cl, 4 dwg