Thread design for uniform distribution of makeup forces
US6848724B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 12, 2002 |
| Grant date | Feb 1, 2005 |
| Priority date | — |
| Expiry date | Oct 21, 2022 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16L15/004
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A threaded pin and box pipe connection having makeup shoulders that contact when the pin and box threads are fully engaged. Upon initial engagement of the shoulders, load flanks of the pin and box threads furthest from the makeup shoulders engage each other and begin progressively separating from each other by an increasing amount along the length of the engaged threads in a direction from the end of the pin to a gauge point of the connection. Upon application of the makeup torque, the separation between the load flanks distributes the torque forces between the makeup shoulders along the length of the engaged threads to prevent concentration of stress forces near the base of the pin thread. The progressive separation of the load flanks is achieved by progressively changing the pitch of the load flank of the pin and/or box thread to vary the thread width. The separation of load flanks is achieved without modifications of the stab flank pitch. The load flank pitch is reduced uniformly along the thread length to effectively achieve a different pitch per unit length. The amount of the load flank thread pitch reduction is equivalent to the makeup, for example, thirty degrees of four thr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.