Drill and lock screw employed for fastening the same
US5338135A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 1992 |
| Grant date | Aug 16, 1994 |
| Priority date | — |
| Expiry date | Apr 9, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T408/90993
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A drill has a pair of cutting edges (4) which are arranged at positions that are substantially uniformly circumferentially spaced about its rotation axis. Each of the cutting edges (4) has a first linear cutting region (4a) and a second linear cutting region (4b) which are aligned with each other on the same straight line, and a curved cutting region (4c) which is located between the first and second linear cutting regions (4a, 4b). The curved cutting region (4c) has a third linear cutting region (4e, 4f) which extends in a direction intersecting with the second linear cutting region (4b) at a prescribed angle. With this structure, it is possible to prevent chip loading etc. which may be caused during perforation drilling operations. In a throw-away tipped drill, a notch (118a) is formed in a received portion of an insert (110) which is mounted on a shank (130). A holding portion (131a, 131b, 133a, 133b) of the shank (130) corresponding to the notch (118a) is provided with a through screw hole (138). A male screw (139) is inserted in the through screw hole (138), and a spherical pressing member (140) is interposed between the forward end of the male screw (139) and the surface of t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.