Prenotched fire-rated runner
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
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Sep 20, 1994
Grant Date -
N/A
app pub date -
Mar 4, 1993
filing date -
Mar 4, 1993
priority date (Note) -
Expired
status (Latency Note)
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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.
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Cited Art Landscape
Patent Citation Ranking
- 16 Citation Count
- E04B Class
- 51.99 % this patent is cited more than
- 31 Age