- All sections
- E - Fixed constructions
- E21D - Shaftstunnelsgallerieslarge underground chambers
- E21D 9/087 - Making by using a driving shield with additional boring or cutting means with a rotary drilling-head cutting simultaneously the whole cross-section, i.e. full-face machines
Patent holdings for IPC class E21D 9/087
Total number of patents in this class: 68
10-year publication summary
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4
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