Fastener and driving tool
US5438895A · kind A · utility
Inventors
Key dates
| Filing date | Apr 29, 1994 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Apr 29, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25B15/007
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A fastening system comprises a driving tool formed with a rectangular-shaped bit at its driving end, and a fastener such as a screw whose head is formed with a recess defining a central slot and four spaced undercuts each having parallel upper and lower walls and a side wall perpendicular thereto. The bit of the driving tool is inserted within the central slot of the recess and then rotated such that the side edges of the rectangular bit contact the side walls of two of the undercuts, and the top wall and bottom surface of the bit frictionally engages the upper and lower walls of such undercuts. Frictional engagement between the undercuts and the driving tool bit provides a positive, temporary interlock therebetween, and contact between the side edges of the driving tool and side walls of the undercuts permits the transfer of torque over a large surface to reduce wear.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.