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CPC Main Group
F01L 21/00

Use of working pistons or pistons-rods as fluid-distributing valves or as valve-supporting elements, e.g. in free-piston machines

Filing statistics

CPC F01L 21/00 belongs to the parent subclass F01L, which recorded 25,057 patent applications worldwide between 2013 and 2023. Annual filings declined from 2,769 in 2013 to 732 in 2023 (-74%), peaking at 3,219 applications in 2015. The most active applicants in class F01 are GE (GENERAL ELECTRIC COMPANY) (9,989 applications), UNITED TECHNOLOGIES CORPORATION (UTC) (8,110 applications) and SAFRAN AIRCRAFT ENGINES (6,248 applications).

Source: EPO PATSTAT, worldwide filings

2 direct subcodes

Child Classifications

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  • F01L 21/02 Piston or piston-rod used as valve members
  • F01L 21/04 Valves arranged in or on piston or piston-rod

Top Applicants

Top 10 applicants by patent filingsfor class F01, 2013–2023, worldwide · Source: EPO PATSTAT

  1. GE (GENERAL ELECTRIC COMPANY) US 9,989
  2. UNITED TECHNOLOGIES CORPORATION (UTC) US 8,110
  3. SAFRAN AIRCRAFT ENGINES FR 6,248
  4. HYUNDAI MOTOR COMPANY KR 4,530
  5. SIEMENS DE 4,461
  6. FORD GLOBAL TECHNOLOGIES US 4,029
  7. RAYTHEON TECHNOLOGIES CORPORATION US 3,947
  8. TOYOTA MOTOR CORPORATION JP 3,734
  9. GE (GENERAL ELECTRIC COMPANY) 3,415
  10. SCHAEFFLER TECHNOLOGIES & COMPANY DE 3,063