E21D
Shafts
Official title: SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS (soil-conditioning or soil-stabilising materials C09K17/00; drilling or cutting machines for mining or quarrying E21C; safety devices, transport, rescue, ventilation or drainage E21F)
E21D (Shafts) appears on 3,603 US grants and 2,065 published applications in this corpus.
Search patents in E21D- Granted patents
- 3,603
- Published applications
- 2,065
- Assignees
- 1,518
- Inventors
- 6,487
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 104 | 0 |
| 1977 | 113 | 0 |
| 1978 | 141 | 0 |
| 1979 | 88 | 0 |
| 1980 | 96 | 0 |
| 1981 | 112 | 0 |
| 1982 | 95 | 0 |
| 1983 | 92 | 0 |
| 1984 | 97 | 0 |
| 1985 | 98 | 0 |
| 1986 | 93 | 0 |
| 1987 | 102 | 0 |
| 1988 | 75 | 0 |
| 1989 | 71 | 0 |
| 1990 | 70 | 0 |
| 1991 | 67 | 0 |
| 1992 | 69 | 0 |
| 1993 | 72 | 0 |
| 1994 | 55 | 0 |
| 1995 | 57 | 0 |
| 1996 | 44 | 0 |
| 1997 | 43 | 0 |
| 1998 | 61 | 0 |
| 1999 | 46 | 0 |
| 2000 | 34 | 0 |
| 2001 | 35 | 12 |
| 2002 | 51 | 36 |
| 2003 | 45 | 45 |
| 2004 | 28 | 42 |
| 2005 | 28 | 50 |
| 2006 | 36 | 55 |
| 2007 | 21 | 65 |
| 2008 | 47 | 46 |
| 2009 | 28 | 66 |
| 2010 | 44 | 85 |
| 2011 | 34 | 78 |
| 2012 | 48 | 85 |
| 2013 | 60 | 74 |
| 2014 | 74 | 98 |
| 2015 | 75 | 110 |
| 2016 | 62 | 85 |
| 2017 | 57 | 102 |
| 2018 | 84 | 100 |
| 2019 | 111 | 106 |
| 2020 | 97 | 135 |
| 2021 | 100 | 111 |
| 2022 | 95 | 106 |
| 2023 | 79 | 113 |
| 2024 | 110 | 106 |
| 2025 | 101 | 79 |
| 2026 | 58 | 75 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Main groups
Granted patents with any code in the group
- E21D 9/00Tunnels or galleries, with or without linings1,090
- E21D 21/00Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection773
- E21D 20/00Setting anchoring-bolts728
- E21D 11/00Lining tunnels, galleries or other underground cavities693
- E21D 23/00Mine roof supports for step- by- step movement491
- E21D 15/00Props206
- E21D 1/00Sinking shafts77
- E21D 19/00Provisional protective covers for working space64
Recent patents
- Device for emptying conveying buckets during the sinking of shafts6 Oct 2026US 12,753,693 B2Herrenknecht AG
- Tunnel boring machine and method for tunneling using a tunnel boring machine29 Sep 2026US 12,747,665 B2Herrenknecht AG
- Double-liquid grouting slurry, its technology and application for super large diameter underwater shield engineering under high water pressure condition22 Sep 2026US 12,741,910 B2China Railway 14th Bureau Group Corporation Limited
- Structural system for building and civil engineering works and construction method15 Sep 2026US 12,735,889 B2
- 3D printing-based device for shield tunnel lining formation8 Sep 2026US 12,728,588 B2Zhejiang University City College
- Dynamic rock bolt assembly8 Oct 2026US 2026/0309029 A1Geomechanical Services and Innovations Inc.
- Rolling Wedge Cutter Drum1 Oct 2026US 2026/0297869 A1
- Method and system for predicting blasting vibration inside surrounding rocks in deep buried tunnels1 Oct 2026US 2026/0298084 A1Northeastern University
- Secondary shaft completion construction method based on raise boring process1 Oct 2026US 2026/0298085 A1China Three Gorges Construction Engineering Corporation
- Hybrid Tunnel Boring Using Combination of Thermal and Mechanical Processes1 Oct 2026US 2026/0298086 A1Phoenix Boring, Inc.
Most cited
By later US patents
- Method for excavating a large diameter shaft into the earth and at least partially through an oil-bearing formation210US 4,597,444 AAtlantic Richfield Company · 1986
- Water cutoff junction member for concrete products to be joined together198US 6,052,960 AYamax Corporation · 2000
- Method of lining a pipe194US 4,009,063 AInsituform (Pipes & Structures) Ltd. · 1977
- 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