Twist drill with unequal flute spacing and unequal relief angles
US10195675B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 2, 2017 |
| Grant date | Feb 5, 2019 |
| Priority date | — |
| Expiry date | Mar 2, 2037 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T408/9097
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A twist drill having a shaft with a longitudinal axis, wherein the cutting tool includes a plurality of flutes extending about the longitudinal shaft along a helix angle and a plurality of lands adjacent the flutes. Each land has a cutting edge adjacent a corresponding flute and a margin (i.e. relief surface). A cutting point is adjacent a forward end of the shaft. A first, second and third forward cutting surfaces are adjacent the first, second and third cutting edges, respectively, and extend proximate the cutting point axially rearward for a predetermined length about the longitudinal axis of the shaft. The cutting edges are unequally angularly spaced from each other, and each forward cutting surface has a primary relief angle that are unequal to each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.