E21D 23/06
Special mine caps or special tops of pit-props for permitting step-by-step movement
E21D23/06 (Special mine caps or special tops of pit-props for permitting step-by-step movement) appears on 72 US grants and 17 published applications in this corpus.
Search patents in E21D- Granted patents
- 72
- Published applications
- 17
- Assignees
- 41
- Inventors
- 113
- Latest grant
- 11 Nov 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 2 | 0 |
| 1977 | 7 | 0 |
| 1978 | 10 | 0 |
| 1979 | 1 | 0 |
| 1980 | 4 | 0 |
| 1981 | 4 | 0 |
| 1982 | 3 | 0 |
| 1983 | 3 | 0 |
| 1984 | 6 | 0 |
| 1985 | 6 | 0 |
| 1986 | 2 | 0 |
| 1987 | 0 | 0 |
| 1988 | 4 | 0 |
| 1989 | 1 | 0 |
| 1990 | 1 | 0 |
| 1991 | 1 | 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 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 1 |
| 2003 | 0 | 1 |
| 2004 | 1 | 0 |
| 2005 | 1 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 0 |
| 2011 | 0 | 1 |
| 2012 | 1 | 2 |
| 2013 | 0 | 1 |
| 2014 | 1 | 0 |
| 2015 | 2 | 1 |
| 2016 | 1 | 1 |
| 2017 | 1 | 3 |
| 2018 | 1 | 1 |
| 2019 | 3 | 2 |
| 2020 | 3 | 1 |
| 2021 | 1 | 1 |
| 2022 | 0 | 0 |
| 2023 | 0 | 1 |
| 2024 | 0 | 0 |
| 2025 | 1 | 0 |
By publication year. Applications have been published since 2001.
Subgroups
Granted patents
Recent patents
- Coal-based solid waste transport and filling integrated machine mining system and method11 Nov 2025US 12,467,362 B2Anhui University of Science and Technology
- Mining rock deflector apparatus and method4 May 2021US 10,995,617 B2Swanson Industries, Inc.
- Mine roof support, pre-installation assembly for same, and method of installation3 Nov 2020US 10,822,948 B2Burrell Mining Products, Inc.
- Apparatus for protecting roof tray when gob-side entry retaining end support migrates3 Nov 2020US 10,822,949 B1China Mining & Civil New Material Science and Technology Ltd.
- Mining rock deflector apparatus and method20 Oct 2020US 10,808,533 B2Swanson Industries, Inc.
- Coal-based solid waste transport and filling integrated machine mining system and method30 Nov 2023US 2023/0383653 A1Western Digital Technologies, Inc.
- Construction method for continuous mining machine having device continuously providing provisional roof support2 Sep 2021US 2021/0270134 A1China University of Mining and Technology
- Mining rock deflector apparatus and method24 Dec 2020US 2020/0400020 A1Swanson Industries, Inc.
- Mining rock deflector apparatus and method21 Nov 2019US 2019/0353035 A1Swanson Industries, Inc.
- Mine roof support, pre-installation assembly for same, and method of installation4 Jul 2019US 2019/0203597 A1Burrell Mining Products, Inc.
Most cited
By later US patents
- Method and apparatus for supporting the roof of an underground mine working14US 4,099,785 A1978
- Shield structure10US 4,020,640 AVereinigte Osterreichische Eisen- und Stahlwerke-Alpine Montan Aktiengesellschaft · 1977
- Shield timbering frame for timbering mines10US 4,236,850 AThyssen Industrie AG · 1980
- Mineral mining installation9US 4,427,321 AGewerkschaft Eisenhutte Westfalia · 1984
- Mine working apparatus7US 4,269,546 AHuwood Limited · 1981