E21D 15/44
Hydraulic, pneumatic, or hydraulic-pneumatic props
Official title: Hydraulic, pneumatic, or hydraulic-pneumatic props {(see also E21D15/51)}
E21D15/44 (Hydraulic, pneumatic, or hydraulic-pneumatic props) appears on 40 US grants and 28 published applications in this corpus.
Search patents in E21D- Granted patents
- 40
- Published applications
- 28
- Assignees
- 34
- Inventors
- 137
- Latest grant
- 13 Jan 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 0 | 0 |
| 1978 | 0 | 0 |
| 1979 | 1 | 0 |
| 1980 | 0 | 0 |
| 1981 | 0 | 0 |
| 1982 | 1 | 0 |
| 1983 | 1 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 1 | 0 |
| 1987 | 1 | 0 |
| 1988 | 1 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 2 | 0 |
| 1992 | 0 | 0 |
| 1993 | 1 | 0 |
| 1994 | 1 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 1 | 0 |
| 1998 | 1 | 0 |
| 1999 | 1 | 0 |
| 2000 | 1 | 0 |
| 2001 | 1 | 0 |
| 2002 | 1 | 2 |
| 2003 | 1 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 1 |
| 2006 | 0 | 0 |
| 2007 | 1 | 0 |
| 2008 | 0 | 0 |
| 2009 | 0 | 2 |
| 2010 | 1 | 1 |
| 2011 | 0 | 0 |
| 2012 | 1 | 0 |
| 2013 | 0 | 5 |
| 2014 | 1 | 3 |
| 2015 | 2 | 2 |
| 2016 | 2 | 1 |
| 2017 | 3 | 2 |
| 2018 | 1 | 0 |
| 2019 | 1 | 0 |
| 2020 | 1 | 2 |
| 2021 | 0 | 2 |
| 2022 | 5 | 1 |
| 2023 | 0 | 0 |
| 2024 | 0 | 0 |
| 2025 | 1 | 4 |
| 2026 | 1 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- 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
- Automatic support device for resisting rock burst in mines15 Apr 2025US 12,276,194 B2
- System for navigation detection and inclination measurement of advanced hydraulic supports4 Oct 2022US 11,459,887 B2Shandong University of Science and Technology
- Hydraulic shield support system and pressure intensifier26 Jul 2022US 11,396,894 B2Caterpillar Global Mining Europe GmbH
- Similar simulation experimental device of hydraulic energy-absorbing roadway support10 May 2022US 11,326,452 B1China University of Mining and Technology
- Suspended moving and adaptive coalburst-preventing hydraulic support with pile foundation18 Sep 2025US 2025/0290416 A1Liaoning University
- Jacking system for excavation construction of cross passage and construction method using the same4 Sep 2025US 2025/0277447 A1Ningbo Yonggong Technology Co., Ltd.
- Asymmetric hydraulic supports for pseudo inclined mining in steeply dipping seam10 Apr 2025US 2025/0116192 A1Xi'an University of Science and Technology
- Automatic support device for resisting rock burst in mines30 Jan 2025US 2025/0034996 A1Shandong University of Science and Technology
- System For Navigation Detection And Inclination Measurement Of Advanced Hydraulic Supports21 Apr 2022US 2022/0120181 A1Shandong University of Science and Technology
Most cited
By later US patents
- Continuously adjustable rescue strut25US 6,394,405 B1Para Tech Incorporated · 2002
- Hydraulic seal with pressure-actuated ridges23US 4,557,488 AHillman Newby Ltd. · 1985
- Temporary mine roof prop19US 4,167,361 AMine Safety Appliances Company · 1979
- Prop for use in underground mining or tunnel construction17US 5,921,718 A1999
- Hydraulic steel mine prop16US 5,051,039 A1991