E21F 1/04
Air ducts
Official title: Air ducts (suspension devices E21F17/02)
E21F1/04 (Air ducts) appears on 28 US grants and 27 published applications in this corpus.
Search patents in E21F- Granted patents
- 28
- Published applications
- 27
- Assignees
- 31
- Inventors
- 83
- Latest grant
- 13 Jan 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 2 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 2 | 0 |
| 1981 | 0 | 0 |
| 1982 | 3 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 0 | 0 |
| 1986 | 1 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 1 | 0 |
| 1993 | 1 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 1 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 2 |
| 2011 | 0 | 0 |
| 2012 | 2 | 1 |
| 2013 | 0 | 3 |
| 2014 | 0 | 1 |
| 2015 | 2 | 1 |
| 2016 | 1 | 4 |
| 2017 | 1 | 2 |
| 2018 | 0 | 2 |
| 2019 | 0 | 0 |
| 2020 | 2 | 2 |
| 2021 | 0 | 2 |
| 2022 | 1 | 1 |
| 2023 | 2 | 2 |
| 2024 | 4 | 2 |
| 2025 | 1 | 2 |
| 2026 | 1 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- System and method for shaping a duct section13 Jan 2026US 12,521,934 B2Plastiques G Plus Inc.
- Coal and gas outburst monitoring device25 Mar 2025US 12,258,865 B2Henan Polytechnic University
- Track structure with center rail31 Dec 2024US 12,179,809 B2RIINO Inc.
- Nuclear island base slab of nuclear power plant, manufacturing method therefor, and nuclear island of nuclear power plant12 Nov 2024US 12,139,868 B2Shanghai Nuclear Engineering Research & Design Institute
- Vertical orthogonal top exhausting air duct structure of deeply-buried subway station and construction method therefor2 Jul 2024US 12,025,008 B2Beijing Urban Construction Design & Development Group Co., Limited
- System and method for shaping a duct section22 May 2025US 2025/0162235 A1Plastiques G Plus Inc.
- Coal and gas outburst monitoring device27 Feb 2025US 2025/0067180 A1Henan Polytechnic University
- Track structure with center rail28 Mar 2024US 2024/0101162 A1RIINO Inc.
- Vertical orthogonal top exhausting air duct structure of deeply-buried subway station and construction method therefor4 Jan 2024US 2024/0003254 A1Beijing Urban Construction Design & Development Group Co., Limited
- Nuclear island base slab of nuclear power plant, manufacturing method therefor, and nuclear island of nuclear power plant14 Sep 2023US 2023/0287645 A1Shanghai Nuclear Engineering Research & Design Institute
Most cited
By later US patents
- Telescopic ventline41US 6,669,552 B12003
- Method and apparatus for extending ventilation ductwork26US 4,625,631 AMobil Oil Corporation · 1986
- Ventilation ducting18US 5,094,273 AAcme Group Pty Ltd. · 1992
- Apparatus for extending ventilating conduits8US 4,361,079 AMaschinenfabrik Korfmann GmbH · 1982
- Ventilation system for automated mining machines5US 4,200,036 AThe United States of America as represented by the Secretary of the Interior · 1980