DRILL ROD CONTAINING EXTENDED INWARD SECTIONS Russian patent published in 2018 - IPC E21B17/00 E21B17/02 E21B17/42 

FIELD: soil or rock drilling.

SUBSTANCE: invention relates to drilling, namely, to drill rods. Threaded component of the drill rod comprises a hollow elongated body, its end section having an internal thread and its opposite end section having an external thread, and a cylindrical section of the middle body extending in the longitudinal direction between the respective end sections with internal and external threads and having a variable wall diameter. Inner wall of the middle body of the middle body section comprises at least one protruding section or burr located at a distance from the end sections with internal and external threads and extending inward towards the central longitudinal axis of the hollow body and towards a number of grooves formed in the inner wall of the middle body of the middle body section.

EFFECT: reducing the weight of the drill rods while maintaining and decreasing the stiffness loss during bending-twisting.

30 cl, 4 dwg, 1 tbl