THREADED JOINT FOR THIN-WALLED METAL PIPES WITH POLYMER OUTER COATING Russian patent published in 1994 - IPC

FIELD: mechanical engineering. SUBSTANCE: outer surface of taper end of male part which is free of thread is engageable with plain taper inner surface of female part, their conicity being equal. Threaded portion of male part and its end are made of polymer flexible material which is identical to and integral with polymer material of coating. Free end is provided with circular fillets forming common conicity. Outer diameter of the largest fillet is less than or equal to the maximum diameter of taper surface of female part. Outer diameter of the minimum fillet exceeds minimum diameter of engageable surface of female part by amount adequate for maximum deformation of all fillets in height within elasticity of polymer material in screwing the threaded parts together. EFFECT: enhanced reliability. 3 dwg