Twist drill and production method
US10252321B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 20, 2015 |
| Grant date | Apr 9, 2019 |
| Priority date | — |
| Expiry date | Dec 8, 2035 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23B2251/408
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method for producing a twist drill has the following steps. A blank is shaped to form a semi-finished product. The semi-finished product is formed from a core, coaxial with the drill axis, having a radius and a number of webs, arranged on the core, having a height. The semi-finished product has a constant cross section along the drill axis. The webs have a first portion which adjoins the core and in which a width of the web remains constant or decreases in the circumferential direction with increasing radial distance from the drill axis. The webs have a second portion which adjoins the first portion and in which the width of the web increases in the circumferential direction with increasing radial distance from the drill axis. The webs of the semi-finished product are shaped into helical segments using a plurality of rolling tools that annularly enclose the semi-finished product and roll on the webs along the drill axis. The rolling tools have teeth that are inclined with respect to the drill axis. A height of the helical segments is less than the height the webs. Helical segments formed from adjacent webs are in contact with one another in a closing fold. The invention also rela…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.