SHOCK ABSORBER FOR DRILL-STEMS Russian patent published in 2017 - IPC E21B17/07 E21B19/18 

FIELD: mining.

SUBSTANCE: according to the first embodiment, the shock absorber for a drill-stem is adapted to be installed in a wellbore. It comprises of an outer tubular body having a multi-thread spiral splined inlet grooves disposed on the inner surface of the body, which contains an upper connecting device for connection to a drill stem and a bottom connecting device for connection to the spring housing and an inner tubular mandrel containing a part of the outer circumferential surface with multi-thread spiral inlet grooves adapted to interface with the multi-thread spiral inlet grooves of the outer tubular body, and, at least, the bottom part of the outer circumferential surface of the mandrel that does not contain grooves. Said inner tubular mandrel is designed for telescopical and rotational reception in the outer tubular body through the inlet grooves included in the spiral inlet grooves of the outer tubular body, and said bottom part of the inner tubular mandrel without grooves is adapted to receive inside the spring housing connected to the outer tubular body. In this case, said inner tubular mandrel has an axial fluid passage for passing a drilling fluid fed through the drill stem over the mandrel. Wherein the spring housing comprises of, at least, one disc spring located around the bottom part of the outer surface of the mandrel without grooves and in the annular space between the mandrel and the inner surface of the spring housing. In addition, said disc spring has a predetermined biasing force which biases, at least, a part of the mandrel outwardly through an axial opening in the upper end of the outer tubular body.

EFFECT: preventing breakdown downtime.

21 cl, 9 dwg