Cold forming tap having internal finish cutting edge and method of producing the same
US6217267A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 17, 1999 |
| Grant date | Apr 17, 2001 |
| Priority date | — |
| Expiry date | Feb 17, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T408/9048
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A cold forming tap with an internal finish cutting edge includes an external thread portion having radially outwardly protruding portions and relief portions which are alternately located in a helical direction in which an external thread extends. The protruding portions are forced into a surface of a prepared hole which has been previously formed through a workpiece, for thereby forming an internal thread on the surface. The improvement comprises: at least one of the protruding portions having a root diameter larger than that of the other of the protruding portions, the at least one of the protruding portions being removed down to a root of the external thread, and a flute being formed in a portion corresponding to the root of the at least one of the protruding portions, so as to provide the cutting edge in the portion corresponding to the root.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.