PUMP ROD Russian patent published in 2020 - IPC E21B17/00 E21B17/04 E21B19/16 

FIELD: drilling of wells.

SUBSTANCE: group of inventions relates to string of pump rods used in oil wells, and more specifically to design of end of pump rod. One-piece metal sucker-rod comprises body of pump rod, transition section, square section for wrench, shoulder section and threaded connecting section. Transition section has an outer surface circumferentially about a longitudinal axis of the transition portion, an outer surface having a longitudinal profile, including a continuous curve starting from the cylindrical outer surface of the rod body and having a concave curved portion with a radius R _A and a convex curved portion with a radius R_B, where R_B is less than R_A, and diameter of transition section, measured across AA longitudinal axis, continuously increases at distance from rod outer surface; section of square for a key, which has at least four sections for a key. Section of external thread collar has collar face adapted to contact with coupling end, where collar face has outer diameter D_F. Threaded connecting section is made with external thread.

EFFECT: technical result is reduction of stress at section of cut for key and in forging zone and reduction of fatigue damages.

18 cl, 5 tbl, 8 dwg