Tamper-resistant fastener and tool for operating same
US4827811A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 11, 1987 |
| Grant date | May 9, 1989 |
| Priority date | — |
| Expiry date | Dec 11, 2007 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16B41/005
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A tamper-resistant torque-responsive fastener is provided having a head and a shank, wherein the head is provided with a socket therein having a substantially triangular shape with rounded corners and curved sides, each of the rounded corners being defined by an arcuate path of a first radius and each curved side generally opposite the rounded corner being defined by the arcuate path of a second radius, whereby the dimensions across the socket remain constant and equal to the sum of the first and second radii. The second radius is of greater length than the first radius and is preferably between 2 and 4 times as long as the first radius. Also provided is a driving tool for operating the fastener.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.