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CPC Subgroup
E21C 25/22

Machines slitting solely by one or more cutter chains moving unidirectionally along jibs

Full Title

Cutting machines, i.e. for making slits approximately parallel or perpendicular to the seam (dislodging machines with slitting means E21C27/02, E21C27/10, E21C27/18) > Machines slitting solely by one or more cutter chains moving unidirectionally along jibs

4 direct subcodes

Child Classifications

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  • E21C 25/24 with flat jibs only
  • E21C 25/26 with curved jibs only
  • E21C 25/50 with equipment for cleaning the slit (associated with rotary-rod or rotary-drum machines E21C25/14)

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