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IPC Subclass
F03C

POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS

Introduced: September 1968

Classification Context

Section:
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Class:
MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
Subclass:
POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS

Description

F03C covers positive-displacement engines and motors powered by pressurized liquids, including hydraulic and hydrostatic systems. This class encompasses reciprocating pumps/motors, rotary vane machines, gear motors, screw motors, and similar devices where liquid flow directly drives mechanical motion through volumetric displacement. Applications include hydraulic power transmission systems, fluid power actuators, and liquid-driven machinery in industrial and mobile equipment. Related classes F03B (water wheels and turbines) and F03D (wind motors) address alternative fluid-driven power sources.

Filing statistics

IPC subclass F03C recorded 4,771 patent applications worldwide between 2013 and 2023. Annual filings declined from 503 in 2013 to 378 in 2023 (-25%), peaking at 559 applications in 2014. The most active applicants in class F03 are VESTAS (3,539 applications), WOBBEN PROPERTIES (2,922 applications) and SIEMENS GAMESA RENEWABLE ENERGY (2,747 applications).

Source: EPO PATSTAT, worldwide filings

5 direct subcodes

Child Classifications

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  • F03C 4/00 Oscillating-piston engines
  • F03C 7/00 Engines of flexible-wall type
  • F03C 99/00 Subject matter not provided for in other groups of this subclass

Top Applicants

Top 10 applicants by patent filingsfor class F03, 2013–2023, worldwide · Source: EPO PATSTAT

  1. VESTAS DK 3,539
  2. WOBBEN PROPERTIES DE 2,922
  3. SIEMENS GAMESA RENEWABLE ENERGY DK 2,747
  4. GE (GENERAL ELECTRIC COMPANY) US 2,356
  5. BEIJING GOLDWIND SCIENCE & CREATION WINDPOWER EQUIPMENT COMPANY 1,228
  6. SIEMENS DE 886
  7. SGCC(STATE GRID CORPORATION OF CHINA) 831
  8. HUANENG CLEAN ENERGY RESEARCH INSTITUTE 785
  9. MING YANG SMART ENERGY GROUP. 652
  10. LM WIND POWER DK 600