Parabolic cover for manhole
US5911537A · kind A · utility
Inventor
Key dates
| Filing date | Feb 6, 1997 |
| Grant date | Jun 15, 1999 |
| Priority date | — |
| Expiry date | Feb 6, 2017 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02D2300/0031
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A manhole cover of substantially monolithic construction is claimed. The manhole cover comprises a central cover portion having a center, and having a thickness that varies radially from the center in accordance with an exponential or parabolic function. An intermediate cover portion surrounds the central cover portion and has a substantially uniform thickness. An outer bearing portion surrounds the intermediate cover portion and has a thickness greater than the intermediate cover portion. The thickness of the central portion may vary radially from the center in accordance with the exponential function, t.sub.r =T.multidot.e.sup.-cB, where t.sub.r is the thickness at a given radial point r from the center, c=(r/R).sup.2, where R is the radius of the cover, B is a dispersion constant, and T is a constant that determines the thickness of the central portion at the center.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.