- All sections
- E - Fixed constructions
- E21D - Shaftstunnelsgallerieslarge underground chambers
- E21D 11/18 - Arch members
Patent holdings for IPC class E21D 11/18
Total number of patents in this class: 55
10-year publication summary
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1
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3
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2
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2
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4
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6
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7
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2
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4
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1
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