Mandrel, bent tube, and method and apparatus for producing bent tube
US11969779B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 2, 2022 |
| Grant date | Apr 30, 2024 |
| Priority date | — |
| Expiry date | Mar 11, 2042 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB21D9/05
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A mandrel 10 for producing a thin-walled bent tube having a bending portion with high strength and a small radius of curvature by rotary draw bending without either cracks in an outside of bend or wrinkles and buckling in an inside of bend occurring includes a shank 14, a connection mechanism 15 and a mandrel ball 16. In a cross-section orthogonal to an axial direction of the mandrel ball 16 at a central position in the axial direction of the mandrel ball 16, the mandrel ball 16 has a first position 19 and a second position 20 at which a first straight line m that passes through a mandrel ball center 17 meets an outer periphery 21 of the mandrel ball. Further, a ratio (L1/L2) between a dimension L1 from the mandrel ball center 17 to the first position 19 and a dimension L2 from the mandrel ball center 17 to the second position 20 is in a range of 0.915 to 0.976.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.