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CPC Subgroup
E21B 19/08

Apparatus for feeding the rods or cables (E21B19/22 takes precedence; automatic feed E21B44/02); Apparatus for increasing or decreasing the pressure on the drilling tool; Apparatus for counterbalancing the weight of the rods

Full Title

Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables > Apparatus for feeding the rods or cables (E21B19/22 takes precedence; automatic feed E21B44/02); Apparatus for increasing or decreasing the pressure on the drilling tool; Apparatus for counterbalancing the weight of the rods

7 direct subcodes

Child Classifications

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  • E21B 19/081 Screw-and-nut feed mechanisms
  • E21B 19/083 Cam, rack or like feed mechanisms
  • E21B 19/084 with flexible drawing means, e.g. cables
  • E21B 19/086 with a fluid-actuated cylinder (E21B19/084, E21B19/087, E21B19/09 take precedence)
  • E21B 19/087 by means of a swinging arm
  • E21B 19/089 with a spring or an additional weight
  • E21B 19/09 specially adapted for drilling underwater formations from a floating support using heave compensators supporting the drill string

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