- All sections
- E - Fixed constructions
- E21D - Shaftstunnelsgallerieslarge underground chambers
- E21D 9/01 - Methods or apparatus for enlarging or restoring the cross-section of tunnels, e.g. by restoring the floor to its original level
Patent holdings for IPC class E21D 9/01
Total number of patents in this class: 5
10-year publication summary
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0
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1
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2
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0
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0
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0
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1
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1
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1
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0
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| 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
Principal owners for this class
| Owner |
All patents
|
This class
|
|---|---|---|
| Komatsu Ltd. | 4557 |
2 |
| Deutsche Bahn AG | 229 |
1 |
| Fuzhou University | 317 |
1 |
| Shenzhen University | 1643 |
1 |
| Other owners | 0 |