- All sections
- E - Fixed constructions
- E21D - Shaftstunnelsgallerieslarge underground chambers
- E21D 9/04 - Driving tunnels or galleries through loose materialsApparatus therefor not otherwise provided for
Patent holdings for IPC class E21D 9/04
Total number of patents in this class: 32
10-year publication summary
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5
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3
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1
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3
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0
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3
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1
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3
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0
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0
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