Printed circuit drill
US3947143A · kind A · utility
21Cited by
3References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 15, 1974 |
| Grant date | Mar 30, 1976 |
| Priority date | — |
| Expiry date | Jul 15, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T408/9097
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A twist drill comprising a bit containing spirally arranged grooves and lands of substantially equal width, with a shank at one end and a pointed tip at the other, the leading edges of the grooves being inclined to the axis of the bit and constituting cutting edges and the lands rearwardly of the cutting edges being relieved, characterized in that there are auxiliary rectilinearly arranged axially spaced cutting edges parallel to the axis of the bit formed by straight line channels spaced peripherally about the axis of the bit but of lesser depth than the spirally arranged grooves.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.