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CPC Main Group
E21C 25/00

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)

14 direct subcodes

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  • E21C 25/20 Machines slitting solely by one or more reciprocating sawing implements or reciprocating cutter chains; Shaker conveyors with cutting means
  • E21C 25/52 Machines incorporating two or more of the slitting means according to groups E21C25/02, E21C25/06, E21C25/16, E21C25/20 and E21C25/22
  • E21C 25/54 Slitting by unguided cutter cables or cutter chains, or by unguided tools drawn along the working face by cables or the like (dislodging by planing means E21C27/32; propulsion by haulage cables E21C29/14)
  • E21C 25/56 Slitting by cutter cables or cutter chains or by tools drawn along the working face by cables or the like, in each case guided parallel to the face, e.g. by a conveyor or by a guide parallel to a conveyor (pressing the conveyor equipped with tools toward the working face E21C35/14)
  • E21C 25/58 Machines slitting by drilling hole on hole
  • E21C 25/60 Slitting by jets of water or other liquid (picks with arrangement of fluid-spraying nozzles E21C35/187; distribution of spraying fluids in rotating cutter-heads E21C35/23)
  • E21C 25/62 Machines for making slits approximately perpendicular to the seams either level with, or above or below the level of, the machine
  • E21C 25/64 Slitting machines guided solely by hand and either carried by hand or mounted on supports (hand-held power-operated tools E21C37/22)
  • E21C 25/66 Machines for making slits with additional arrangements for drilling
  • E21C 25/68 Machines for making slits combined with equipment for removing, e.g. by loading, material won by other means (slitting machines combined with planing means E21C27/18; removing chippings E21C35/20)

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