CPC Subgroup
E21C 27/02 solely by slitting (rods, drums, for same E21C25/10; saws, discs, wheels E21C25/18; chains, chain guides, for same E21C25/28)
Full Title
Machines which completely free the mineral from the seam > solely by slitting (rods, drums, for same E21C25/10; saws, discs, wheels E21C25/18; chains, chain guides, for same E21C25/28)
2 direct subcodes
Child Classifications
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- E21C 27/04 by a single chain guided on a frame with or without auxiliary slitting means
- E21C 27/08 with additional means for cutting the mineral into blocks
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