Eccentric knockouts for metal boxes
US4640433A · kind A · utility
21Cited by
7References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1985 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Nov 21, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02G3/085
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A knockout structure is provided for selectively forming openings for either one of two different sizes of conduit. The center of the inner knockout is offset from the center of the outer knockout, creating an eccentric relationship which permits a positive ground to be established between the smaller conduit and the box wall by a standard lock washer when the smaller conduit is mounted therein. A secure mechanical connection is similarly established.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.