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CPC Subgroup
E21B 1/16

with spring-mounted reciprocating masses, e.g. with air cushion

Full Title

Percussion drilling > with a reciprocating impulse member (E21B1/02, E21B1/38 take precedence) > driven by a rotating mechanism > with spring-mounted reciprocating masses, e.g. with air cushion

1 direct subcode

Child Classifications

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  • E21B 1/18 with elastic joining of the drive to the push-rod by double buffer springs

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