Tube expanding bullet and method of expanding tube
US6318145A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 18, 2000 |
| Grant date | Nov 20, 2001 |
| Priority date | — |
| Expiry date | Aug 18, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB21D39/20
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A tube expanding bullet is inserted into and expands a heat exchanger tube which has been pierced through collared fin holes of piled heat exchanging fins, so as to expand the fin holes and integrate the tube with the heat exchanging fins. The tube expanding bullet has a first part formed at a front part of the tube expanding bullet and a second part formed at a rear part of the tube expanding bullet whose maximum outer diameter is greater than that of the first part. The fin holes are firstly expanded by passing the first part of the bullet through the tube. The fin hole is secondly expanded by passing the second part of the bullet through the tube. A first rate of expansion of the fin hole by the first part of the tube expanding bullet is less than a second rate of expansion of the fin hole by the second part of the bullet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.