Prenotched fire-rated runner
US5347783A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1993 |
| Grant date | Sep 20, 1994 |
| Priority date | — |
| Expiry date | Mar 4, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S52/05
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The grid member is formed of sheet metal and has an inverted T-shape with a bulb at the top, a double thickness central web and oppositely disposed flanges at the bottom. To achieve controlled expansion, two parallel lances are cut along opposite sides of the bulb near the top of the bulb. No metal is removed at this area of maximum bending stress. Further, staggered cutouts are placed in the two thicknesses which make up the web. By staggering the cutout areas of adjacent web layers, the overall web strength is maintained. These web cutouts and the lance at the top of the bulb cooperate upon thermal expansion, causing the bottom flanges to buckle down, and the web and sides of the bulb to separate laterally and fold, and the top of the bulb to buckle up. The folded web configuration directed by the staggered cutout pattern will maintain longitudinal rigidity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.