E21D 21/004
Bolts held in the borehole by friction all along their length, without
Official title: {Bolts held in the borehole by friction all along their length, without additional fixing means}
E21D21/004 (Bolts held in the borehole by friction all along their length, without) appears on 84 US grants and 75 published applications in this corpus.
Search patents in E21D- Granted patents
- 84
- Published applications
- 75
- Assignees
- 45
- Inventors
- 160
- Latest grant
- 21 Apr 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 1 | 0 |
| 1978 | 1 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 2 | 0 |
| 1982 | 8 | 0 |
| 1983 | 3 | 0 |
| 1984 | 4 | 0 |
| 1985 | 3 | 0 |
| 1986 | 0 | 0 |
| 1987 | 6 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 1 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 1 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 1 | 0 |
| 1998 | 2 | 0 |
| 1999 | 1 | 0 |
| 2000 | 0 | 0 |
| 2001 | 1 | 0 |
| 2002 | 0 | 0 |
| 2003 | 0 | 0 |
| 2004 | 0 | 4 |
| 2005 | 2 | 3 |
| 2006 | 2 | 3 |
| 2007 | 1 | 5 |
| 2008 | 3 | 4 |
| 2009 | 2 | 2 |
| 2010 | 1 | 2 |
| 2011 | 2 | 3 |
| 2012 | 2 | 2 |
| 2013 | 0 | 5 |
| 2014 | 5 | 2 |
| 2015 | 2 | 5 |
| 2016 | 2 | 4 |
| 2017 | 2 | 4 |
| 2018 | 5 | 6 |
| 2019 | 3 | 3 |
| 2020 | 2 | 4 |
| 2021 | 4 | 3 |
| 2022 | 2 | 1 |
| 2023 | 2 | 1 |
| 2024 | 1 | 4 |
| 2025 | 2 | 3 |
| 2026 | 2 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Dynamic rockbolt21 Apr 2026US 12,607,123 B2FCI Holdings Delaware, Inc.
- High capacity rock bolt7 Apr 2026US 12,595,736 B2FCI Holdings Delaware, Inc.
- Rock bolt16 Dec 2025US 12,497,891 B2Sandvik Mining and Construction Australia (Production/Supply) Pty Ltd
- Double-wedge rock bolt11 Nov 2025US 12,467,361 B2Sandvik Mining and Construction Australia (Production/Supply) Pty Ltd
- Drilling assembly for inserting a rock bolt21 May 2024US 11,988,094 B2
- Rock bolt17 Sep 2026US 2026/0275866 A1Sandvik Mining and Construction Australia (Production/Supply) Pty Ltd
- Rock bolt13 Aug 2026US 2026/0235029 A1Sandvik Mining and Construction Australia (Production/Supply) Pty Ltd
- Rock bolt installation2 Oct 2025US 2025/0305416 A1Sandvik Mining and Construction Australia (Production/Supply) Pty Ltd
- Dynamic Rockbolt19 Jun 2025US 2025/0198288 A1FCI Holdings Delaware, Inc.
- Rock bolt30 Jan 2025US 2025/0034998 A1Sandvik Mining and Construction Australia (Production/Supply) Pty Ltd
Most cited
By later US patents
- Method of rock bolting and rock bolt122US 4,511,289 AAtlas Copco Aktiebolag · 1985
- Method and installation apparatus for rock bolting121US 4,423,986 AAtlas Copco Aktiebolag · 1984
- Method of rock bolting and tube-formed expansion bolt114US 4,634,317 AAtlas Copco Aktiebolag · 1987
- Friction rock stabilizers32US 4,012,913 A1977
- Earth structure stabilizer30US 4,284,379 AIngersoll-Rand Company · 1981