# US 7,607,333 B2 · Helical groove for a tubular connection

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- Number: US 7,607,333 B2
- Document ID: US7607333B2
- Status: Granted
- Kind: B2
- Application number: 11/627,157
- Filed: 2007-01-25
- Published: 2007-06-14
- Granted: 2009-10-27
- Earliest claimed: 2004-10-05
- Assignees: Hydril Company
- Inventors: Robert S. Sivley, IV; Harris A. Reynolds, Jr.
- Web page: https://patentgrep.com/patent/US7607333B2

## CPC

- F16L 15/004: {with axial sealings having at least one plastically deformable sealing surface (with sealing rings F16L15/003)}
- F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL

## Abstract

A tubular connection and methods of manufacturing a box member. The tubular connection includes a box member that includes an internal thread and a pin member that includes an external thread. The external thread is adapted to threadedly engage the internal thread. A substantially helical groove is formed on an outer surface of the box member. The method of manufacturing the box member includes selecting an outer diameter for a box member that causes the tool joint to have a greater than a selected bending strength ratio. A helical groove is formed on the outer diameter of the box member such that the helical groove reduces the bending strength ratio to be about the selected bending strength ratio. An internal thread is formed on an internal surface of the box member. Another method of manufacturing the box member includes forming an internal thread on an internal surface of a cylinder and forming a substantially helical groove on an outer surface of the cylinder. The substantially helical groove is positioned substantially in-lead with the internal thread.

## Claims

### Claim 1

A method to manufacture a tool joint including a pin member and a box member, the method comprising:
selecting a desired bending strength ratio for the box member;
forming an outer diameter for the box member to exceed the selected bending strength ratio;
forming a helical groove in the formed outer diameter;
reducing a bending strength ratio of the box member with the formed helical groove to the selected bending strength ratio;
forming an internal thread on an internal surface of the box member; and
forming an external thread on an external surface of the pin member, wherein the external thread is adapted to threadably engage the internal thread.

### Claim 2 (depends on 1)

The method of claim 1, wherein the helical groove is positioned substantially in-lead with the internal thread.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
forming a first seal surface on the internal surface of the box member; and
forming a second seal surface on the external surface of the pin member;
wherein the first and second seal surfaces are adapted to form a seal after radial plastic expansion of the tool joint.

### Claim 4 (depends on 1)

The method of claim 1, wherein the internal thread and external thread comprise substantially dovetail-shaped threads.

### Claim 5 (depends on 1)

The method of claim 1, wherein the helical groove has a profile selected from the group consisting of trapezoidal, V-shaped, parabolic, U-shaped, and semi-circular cross sections.

### Claim 6 (depends on 1)

The method of claim 1, wherein the helical groove has a cross section that varies along an axial length of the box member.

### Claim 7 (depends on 1)

The method of claim 1, wherein the internal thread and the external thread comprise wedge threads.

### Claim 8 (depends on 7)

The method of claim 7, wherein a width of the helical groove varies at a rate substantially equal to a varying of a width of crests of the internal thread.

### Claim 9 (depends on 7)

The method of claim 7, wherein the internal thread and external thread are substantially dovetail-shaped threads.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
forming a first seal surface and a second seal surface on the internal surface of the box member; and
forming a third seal surface and a fourth seal surface on the external surface of the pin member;
wherein the first and third seal surfaces are adapted to form a seal against an external pressure upon engagement thereof; and
wherein the second and fourth seal surfaces are adapted to form a seal against an internal pressure upon engagement thereof.

### Claim 11 (depends on 10)

The method of claim 10, further comprising:
forming a groove on the internal surface of the box member proximate the second seal surface, wherein the groove is adapted to receive a sealing ring.

### Claim 12 (depends on 10)

The method of claim 10, further comprising:
forming a groove on the external surface of the pin member proximate the third seal surface, wherein the groove is adapted to receive a sealing ring.