Manhole riser
US4143988A · kind A · utility
4Cited by
5References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 28, 1978 |
| Grant date | Mar 13, 1979 |
| Priority date | — |
| Expiry date | Jul 28, 1998 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02D29/1409
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A manhole extension or riser for increasing the height of manhole cover frames when a roadway is resurfaced. It includes roadbed piercing anchors attached to the periphery of a simple ring increasing the height of the frame. The anchors, made of flat steel plates cut into trapezoids, act to lock the riser in place when the new road surface is laid down. A second ring is used to increase the height of the cover support lift.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.