US 6,581,980 B1 · Threaded connection with high compressive rating

Abstract

The surface areas available for absorbing compressive loading of a threaded connection are increased by increasing the engaged area of a torque shoulder in the connection and by reducing the spacing between the stab flanks of the threads. The areas are increased by increasing the dimensions of the components and by decreasing the machine tolerances permitted in manufacturing the components. The gap in the connection adjacent the torque shoulder is reduced so that the contact surface area of the torque shoulder is increased while the close proximity of the surrounding cylindrical walls of the connection reduces voids that can receive plastic deformation of the torque shoulder corners. The surfaces adjacent the torque shoulder are cylindrical in shape rather than being tapered to reduce machining costs and increase the speed of manufacture of the connection. The compressive loading of the connection provides an axial seal along the bearing surface with the torque shoulder and a radial seal in the near adjacent area of the surrounding cylindrical walls. An interference seal at the end of the box face and the pin nose isolates the engaged threads from the corrosive effects of fluids on either side of the connection. The provision of cylindrical walls in the threaded area reduces side wall galling, enables easier gauging and machining, and provides an increased contact area in the cylindrical surrounding areas.

Claims34

Dependent claims

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.

9 more elements

Dependencies are inferred from the claim text.

Threaded connection with high compressive rating

Life of this patent

Threaded connection with high compressive rating

Life of this patent

Abstract

Claims34