THREAD PROFILE PROVIDING REDUCED STRESSES Russian patent published in 2020 - IPC E21B17/42 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to threaded connections widely used in oil and gas industry for connection of one or more devices together. Thread profile for a threaded connection comprises a threaded element with a plurality of turns extending from the first end to the second end. At least part of each of the thread turns comprises a vertex, a recess having a rounded zone of recess extending from the point central relative to the recess, and flat side surfaces passing from both sides of the rounded zone of the recess. Diameter of thread turns formed by vertices and cavities is constant along length of threaded element. Flat side surfaces comprise a first lateral surface and a second side surface located at different angles relative to the top. Threaded connection contains a male threaded element containing multiple turns of external thread, and covering a threaded element connected to a male threaded element. Edge of at least one turn of external thread is in contact with one of flat side surfaces of at least one turn of internal thread with prevention of contact of upper point of top of outer thread coil and flat side surfaces of internal thread and with prevention of contact of flat side surfaces of external thread and flat side surfaces of internal thread.

EFFECT: technical result is improved reliability of threaded joint due to change of direction of shearing forces leading to reduction of accumulation of fatigue stresses.

17 cl, 12 dwg