E21F 17/12
Dam doors
Official title: Dam doors {(air doors E21F1/10; air locks E21F1/145)}
E21F17/12 (Dam doors) appears on 6 US grants and 1 published applications in this corpus.
Search patents in E21F- Granted patents
- 6
- Published applications
- 1
- Assignees
- 1
- Inventors
- 3
- Latest grant
- 7 Mar 2000
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1978 | 3 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 0 | 0 |
| 1982 | 0 | 0 |
| 1983 | 1 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 0 | 0 |
| 2000 | 1 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 0 | 1 |
By publication year. Applications have been published since 2001.
Recent patents
- Door system for a mine stopping7 Mar 2000US 6,032,986 AJack Kennedy Metal Products & Buildings, Inc.
- Door frame and door assembly for a mine stopping18 Jun 1985US 4,523,406 A
- Door for a mine stopping having knife-edge hinges15 Feb 1983US 4,373,294 A
- Door frame and door assembly for a mine stopping10 Oct 1978US 4,118,894 A
- Mine stopping device and method of constructing same27 Jun 1978US 4,096,702 A
Most cited
By later US patents
- Door frame and door assembly for a mine stopping25US 4,118,894 A1978
- Mine stopping device and method of constructing same17US 4,096,702 A1978
- Door for a mine stopping having knife-edge hinges11US 4,373,294 A1983
- Door for a mine stopping10US 4,082,331 A1978
- Door system for a mine stopping9US 6,032,986 AJack Kennedy Metal Products & Buildings, Inc. · 2000