Threaded Connection

摘要

A threaded connection for use on oil field tubular. The connection has a dual tapered thread comprising a dual helical thread having a first, straight threaded portion and a second, angled portion, the threaded connection comprising a pin connection and a box connection both of which have thread-free sections. The thread-free section on the pin and the box are comprised of frustoconical surfaces and cylindrical surfaces. The thread-free section of the pin in addition to having a frustoconical surface and a cylindrical surface has an annular, radially outwardly radiused protrusion which, when the box and the pin connection are made-up is in interference engagement with the frustoconical surface in the box.

主权项

1. A threaded connection comprising:
a pin connection having an O.D., a long axis coaxial with said O.D., and a pin end, said pin connection comprising an externaly threaded portion having a first threaded portion with a substantially zero angle of thread taper with respect to said long axis of said pin connection and a second threaded portion having an angle of thread taper of from about 4.722° to about 4.807° with respect to said long axis of said pin connection, said first and second threaded portions of said pin connection being formed by a continuous helical thread, said pin connection having a pin nose on said pin end, there being a pin thread-free section on said pin connection extending from said pin nose to about said first thread of said first threaded portion of said pin connection, said pin thread-free section having a first thread-free section forming an external pin cylindrical surface proximal said first threaded section of said pin connection and extending axially toward said pin nose, and a second thread-free section extending from said pin nose axially toward said first threaded portion said second thread-free section having a pin frustoconical surface adjacent said pin nose and an annularly extending, radially outwardly projecting, radiused pin protrusion inter connecting said pin frustoconical surface and said pin cylindrical surface; a box connection for threadedly receiving said pin connection, said box connection comprising an internal threaded portion having first and second internal threaded portions complementary to said first and second external threaded portions of said pin connection, said internal threaded portion of said box connection being formed by a continuous helical thread, said box connection having an annular, internal shoulder, there being a box thread-free section extending from said shoulder to the first threaded portion of said box connection, said box thread-free section including an internal, box cylindrical surface proximal said first threaded portion of said box connection and extending axially toward said shoulder, at least a portion of said box thread-free section including an internal, box frustoconical surface extending from proximal said shoulder and intersecting said box cylindrical surface; and said pin nose engaging said annular shoulder and said pin protrusion being in interference engagement with said box frustoconical surface when said threaded connection is made-up, said interference engagement upon make-up resulting in radially inward swaging of said thread-free section of said pin connection proximal said pin nose.