E21D 23/03
Mine roof supports for step- by- step movement: having protective means
Official title: having protective means, e.g. shields, for preventing or impeding entry of loose material into the working space or support
E21D23/03 (Mine roof supports for step- by- step movement: having protective means) appears on 36 US grants and 20 published applications in this corpus.
Search patents in E21D- Granted patents
- 36
- Published applications
- 20
- Assignees
- 31
- Inventors
- 95
- Latest grant
- 18 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 2 | 0 |
| 1977 | 4 | 0 |
| 1978 | 7 | 0 |
| 1979 | 0 | 0 |
| 1980 | 3 | 0 |
| 1981 | 1 | 0 |
| 1982 | 0 | 0 |
| 1983 | 1 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 0 | 0 |
| 1987 | 1 | 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 | 1 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 1 | 0 |
| 2003 | 0 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 0 |
| 2006 | 0 | 1 |
| 2007 | 0 | 1 |
| 2008 | 1 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 2 |
| 2011 | 0 | 3 |
| 2012 | 0 | 1 |
| 2013 | 3 | 1 |
| 2014 | 1 | 1 |
| 2015 | 0 | 2 |
| 2016 | 2 | 0 |
| 2017 | 1 | 0 |
| 2018 | 0 | 0 |
| 2019 | 0 | 0 |
| 2020 | 0 | 1 |
| 2021 | 0 | 0 |
| 2022 | 0 | 0 |
| 2023 | 1 | 3 |
| 2024 | 1 | 1 |
| 2025 | 2 | 1 |
| 2026 | 2 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- System and method for controlling roof support18 Aug 2026US 12,709,982 B2Joy Global Underground Mining LLC
- Asymmetric hydraulic supports for pseudo inclined mining in steeply dipping seam13 Jan 2026US 12,523,151 B2XI'AN UNIVERSITY OF SCIENCE AND TECHNOLOGY Xi'an, China
- Coal-based solid waste transport and filling integrated machine mining system and method11 Nov 2025US 12,467,362 B2Anhui University of Science and Technology
- Hydraulic support with quick response function for coal wall spalling8 Jul 2025US 12,352,169 B2Shandong University of Science and Technology
- Distributed coal cutting device for longwall face of coal mine30 Jul 2024US 12,049,824 B2
- Underground mining system and method30 Jul 2026US 2026/0218612 A1
- Method for reliability assessment of shield tunnel structure based on joint safety reserve18 Jun 2026US 2026/0168380 A1Tongji University
- Asymmetric hydraulic supports for pseudo inclined mining in steeply dipping seam10 Apr 2025US 2025/0116192 A1Xi'an University of Science and Technology
- Hydraulic Support with Quick Response Function for Coal Wall Spalling25 Jan 2024US 2024/0026788 A1Shandong University of Science and Technology
- Coal-based solid waste transport and filling integrated machine mining system and method30 Nov 2023US 2023/0383653 A1Western Digital Technologies, Inc.
Most cited
By later US patents
- Assembly for preventing the fall of dust and debris in a mine18US 4,003,208 A1977
- Mine roof support and method in longwall mining of thick mineral seams17US 4,065,929 AAtlantic Richfield Company · 1978
- Mine roof support14US 4,010,618 ADowty Mining Equipment Limited · 1977
- Method for the controlled maintaining of a distance between the top canopy and the coal face in longwall mining operations14US 8,567,870 B2RAG Aktiengesselschaft · 2013
- Method for producing a face opening using automated systems9US 8,708,421 B2RAG Aktiengesellschaft · 2014