CPC Subgroup
E21D 9/10 Making by using boring or cutting machines (E21D9/08 takes precedence; mining picks E21C35/18)
Full Title
Tunnels or galleries, with or without linings; Methods or apparatus for making thereof (E02D29/045, E02D29/063 take precedence; linings per se E21D11/00); Layout of tunnels or galleries > Making by using boring or cutting machines (E21D9/08 takes precedence; mining picks E21C35/18)
9 direct subcodes
Child Classifications
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- E21D 9/11 with a rotary drilling-head cutting simultaneously the whole cross-section, i.e. full-face machines
Top Applicants
Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT
- HALLIBURTON ENERGY SERVICES GROUP US 27,652
- SAUDI ARABIAN OIL COMPANY SA 7,755
- PETROCHINA COMPANY 7,025
- BAKER HUGHES US 6,589
- SCHLUMBERGER TECHNOLOGY US 6,151
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
- SCHLUMBERGER TECHNOLOGY NL 4,255
- CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
- SERVICES PETROLIERS SCHLUMBERGER FR 3,300
- SCHLUMBERGER CANADA CA 3,086