E21D 23/16
Hydraulic or pneumatic features
Official title: Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices
E21D23/16 (Hydraulic or pneumatic features) appears on 122 US grants and 39 published applications in this corpus.
Search patents in E21D- Granted patents
- 122
- Published applications
- 39
- Assignees
- 53
- Inventors
- 161
- Latest grant
- 11 Nov 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 3 | 0 |
| 1978 | 4 | 0 |
| 1979 | 5 | 0 |
| 1980 | 6 | 0 |
| 1981 | 7 | 0 |
| 1982 | 3 | 0 |
| 1983 | 7 | 0 |
| 1984 | 11 | 0 |
| 1985 | 7 | 0 |
| 1986 | 7 | 0 |
| 1987 | 4 | 0 |
| 1988 | 3 | 0 |
| 1989 | 1 | 0 |
| 1990 | 4 | 0 |
| 1991 | 3 | 0 |
| 1992 | 0 | 0 |
| 1993 | 1 | 0 |
| 1994 | 0 | 0 |
| 1995 | 2 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 1 | 0 |
| 2000 | 1 | 0 |
| 2001 | 0 | 0 |
| 2002 | 2 | 1 |
| 2003 | 3 | 1 |
| 2004 | 0 | 2 |
| 2005 | 0 | 1 |
| 2006 | 1 | 8 |
| 2007 | 2 | 2 |
| 2008 | 6 | 0 |
| 2009 | 2 | 0 |
| 2010 | 0 | 0 |
| 2011 | 0 | 0 |
| 2012 | 0 | 2 |
| 2013 | 0 | 2 |
| 2014 | 2 | 1 |
| 2015 | 2 | 4 |
| 2016 | 5 | 2 |
| 2017 | 0 | 0 |
| 2018 | 1 | 0 |
| 2019 | 1 | 0 |
| 2020 | 2 | 3 |
| 2021 | 2 | 1 |
| 2022 | 3 | 1 |
| 2023 | 1 | 4 |
| 2024 | 2 | 2 |
| 2025 | 4 | 1 |
| 2026 | 0 | 1 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
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
- External fluid bar for fluid driven cylinder4 Nov 2025US 12,460,546 B1
- Secured gland for fluid-powered cylinder28 Oct 2025US 12,454,968 B1
- Hydraulic support with quick response function for coal wall spalling8 Jul 2025US 12,352,169 B2Shandong University of Science and Technology
- Mining shield base lift methods12 Nov 2024US 12,138,721 B2
- Underground mining system and method30 Jul 2026US 2026/0218612 A1
- Roof Support Unit for a Mining Machine22 May 2025US 2025/0163807 A1Caterpillar Inc.
- Digital speed regulating valve for aligning hydraulic supports in fully mechanized mining face and control method thereof5 Dec 2024US 2024/0401480 A1Taiyuan University of Technology
- Hydraulic Support with Quick Response Function for Coal Wall Spalling25 Jan 2024US 2024/0026788 A1Shandong University of Science and Technology
- Mining shield base lift methods21 Dec 2023US 2023/0405740 A1Swanson Industries, Inc.
Most cited
By later US patents
- Multi-core hydraulic duct27US 4,149,567 AGewerkschaft Eisenhutte Westfalia · 1979
- Method and device for monitoring the load on hydraulic powered shield supports for underground mining18US 6,056,481 ADBT Automation GmbH · 2000
- Control system for longwall face alignment16US 6,481,802 B1Tiefenbach Bergbautechnik GmbH · 2002
- Mine roof support14US 4,010,618 ADowty Mining Equipment Limited · 1977
- Hydraulic coupling device13US 4,247,135 AGewerkschaft Eisenhutte Westfalia · 1981