Manhole cover locking bolt construction
US4723866A · kind A · utility
55Cited by
5References
11Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1985 |
| Grant date | Feb 9, 1988 |
| Priority date | — |
| Expiry date | Jun 19, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S411/91
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A manhole cover locking bolt construction for locking a manhole cover to an associated frame including a bolt having a threaded shank and an externally threaded head and an endless curvilinear groove in the top of the head for receiving a key of mating configuration for threading the bolt into and out of the manhole cover frame, and a cap for threadably mounting on the externally threaded head to protect the curvilinear groove against entry of foreign matter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.