Thread joint for tube
US5649725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1995 |
| Grant date | Jul 22, 1997 |
| Priority date | — |
| Expiry date | Oct 17, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16L15/004
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A thread joint for a tube which suppresses galling without deteriorating its sealing performance since a sliding distance L.sub.S which expresses a quantity of spiral sliding of sealing portions relative to each other during a tightening period from the start of a contact between the sealing portions until shoulder portions abut each other satisfies the following relationship: Sliding Distance L.sub.S .ltoreq.-0.0093.times. (Tube Outer Diameter).sup.2 +4.73.times. (Tube Outer Diameter). To shorten the sliding distance L.sub.S, the sealing portion of a box portion is formed shorter than the sealing portion of a pin portion. In this case, a circumferential groove may be formed to discharge a dope. Conversely, the sealing portion of the pin portion is formed shorter than the sealing portion of the box portion. In this case, a precedent-stage unthread portion whose inclination is smaller than that of the sealing portion of the pin portion is formed between a male thread and the sealing portion of the pin portion. In addition, tapers of the sealing portions of the pin portion and the box portion are set at 1/6 or larger, and/or, a distance where the sealing portion of the box portion (p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.