Manhole insert for manufacture of a cast member and to provide a step insert having increased structural and holding strength
US7108101B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 1999 |
| Grant date | Sep 19, 2006 |
| Priority date | — |
| Expiry date | Oct 12, 2022 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB28B21/566
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Method and apparatus for forming cast members. Steps are provided in the cast member by sliding mounting flanges of hollow plastic step inserts into slots provided in the inner mold shell. The cast material is then poured into the mold. Once the cast material has set, the cast member is withdrawn from the mold assembly. The step insert mounting flanges are broken away, leaving hollow step inserts into which manhole steps are force-fittingly mounted. The inserts are provided with integral cover tabs which cover larger slots provided to facilitate insertion of the step inserts, preventing leakage of the cast material into the mold assembly. Integral cover tabs are similarly provided on enforcement ring support members mounted in a similar fashion to insertion slots provided on one of the mold members to cover larger width slot portions to prevent seepage of cast material. Similar seals are provided by cylindrical-shaped inserts for use in wetcast and drycast fabrication methods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.