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PCE
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CPC Subgroup
E21C 27/04

by a single chain guided on a frame with or without auxiliary slitting means

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) > by a single chain guided on a frame with or without auxiliary slitting means

1 direct subcode

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Top Applicants

Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT

  1. HALLIBURTON ENERGY SERVICES GROUP US 27,652
  2. SAUDI ARABIAN OIL COMPANY SA 7,755
  3. PETROCHINA COMPANY 7,025
  4. BAKER HUGHES US 6,589
  5. SCHLUMBERGER TECHNOLOGY US 6,151
  6. SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
  7. SCHLUMBERGER TECHNOLOGY NL 4,255
  8. CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
  9. SERVICES PETROLIERS SCHLUMBERGER FR 3,300
  10. SCHLUMBERGER CANADA CA 3,086