Patent ID: 6581980
Filing Date: 2003-06-24
Classification: E21B,F16L

Abstract:
A threaded connection for securing tubular bodies together comprising:an axially extending thread member having an external area provided with pin threads having a stab flank and a load flank; an axially extending box member having an internal area provided with box threads having a stab flank and a load flank, said box threads adapted to threadedly engage with said pin threads along a common axis of said pin member and said box member; a pin torque shoulder provided on said pin member, said pin torque shoulder formed between first and second cylindrical pin surfaces having different diameters and formed coaxially with said pin members on said external area; a box torque shoulder provided on said box member, said box torque shoulder formed between first and second cylindrical box surfaces having differing diameters and formed coaxially with said box member on said internal area, said box torque shoulder adapted to engage said pin torque shoulder to axially limit the threaded engagement of said pin and said box; and wherein the diameter of said first cylindrical box surface is selected to be larger than the diameter of said first cylindrical pin surface by an amount sufficient to confine the torque shoulders of said pin and said box to limit plastic deformation of said torque shoulders into voids between said cylindrical pin and box surfaces when said pin and box torque shoulders are plastically deformed by compression loading of said connections; and wherein the axial spacing between said stab flanks of said engaged pin and box threads is less than 0.0200 inches before said connection is loaded in compression; and wherein said stab flanks of said pin threads and said box threads are dimensioned to close and become engaged at a compression load of said connection below that causing plastic deformation of said pin or box torque shoulders whereby said compressive load is distributed over said pin and box threads and said torque shoulders for increasing the compression load rating of said connection; and wherein said box threads are widened axially relative to said pin threads to reduce the stab flank spacing between said engaged pin and box threads when engaged.