HEAD OF CORE STRING ASSEMBLY WITH SAFETY OVER-THROW Russian patent published in 2020 - IPC E21B25/02 

FIELD: soil or rock drilling; mining.

SUBSTANCE: group of inventions relates to a core of a core pipe assembly and a method of underground drilling. Head of core tube assembly comprises: upper housing comprising central passage; a pair of retainers located in central passage; a retractable body including a first end configured to engage at least a retainer release device. Each retainer comprises a hook at the first end and a hinge on the outer surface in the hook. Hook of each retainer extends through the hook slot so that the retainers rotate around the hinge. Each retainer rotates around the hinge at the first end and comprises a retainer release device at the second end and a surface engaging the outer tube surface between the first end and the second end. Surface of each retainer engaging surface of external pipe extends through retainer slot in outer wall of upper housing so that retainers turn around hinge. Fasteners are made with possibility to move the cleaning body between the extended position and the retracted position with gain in force.

EFFECT: technical result consists in reliable fastening of core pipe inside drill string.

20 cl, 26 dwg