Insert forming hole to receive manhole step
US6315077A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 1998 |
| Grant date | Nov 13, 2001 |
| Priority date | — |
| Expiry date | Aug 20, 2018 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE06C9/04
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A frangible insert that is inserted in a pre-positioned bushing in the wall of a manhole form from the convex, easily reached side of the inner form wall. A key in the insert is received in a keyway in the bushing in the form wall so that the insert is properly oriented in the form. Concrete is then poured into the form, enveloping and affixing the insert within the man hole wall. A weakened, frangible region is provided on the insert in a position immediately adjacent to the form wall so that after the concrete is cured, the manhole and form can simply be separated, causing the portion of the insert embedded in the concrete to separate from the insert portion in the form bushing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.