F03C POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS (positive- displacement engines for liquids and elastic fluids F01; positive- displacement machines for liquids F04; fluid-pressure actuators F15B; fluid gearing F16H)
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
CPC subclass F03C recorded 3,545 patent applications worldwide between 2013 and 2023. Annual filings declined from 328 in 2013 to 236 in 2023 (-28%), peaking at 441 applications in 2014. The most active applicants in class F03 are VESTAS (3,718 applications), WOBBEN PROPERTIES (3,602 applications) and SIEMENS GAMESA RENEWABLE ENERGY (3,016 applications).
Source: EPO PATSTAT, worldwide filings
5 direct subcodes
Child Classifications
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- F03C 1/00 Reciprocating-piston liquid engines
- F03C 2/00 Rotary-piston engines (in which the liquid exclusively displaces one or more piston reciprocating in rotary cylinders F03C1/24)
- 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
- VESTAS DK 3,718
- WOBBEN PROPERTIES DE 3,602
- SIEMENS GAMESA RENEWABLE ENERGY DK 3,016
- GE (GENERAL ELECTRIC COMPANY) US 2,594
- SIEMENS DE 1,082
- BEIJING GOLDWIND SCIENCE & CREATION WINDPOWER EQUIPMENT COMPANY 709
- LM WIND POWER DK 671
- WOBBEN PROPERTIES 660
- SENVION DE 555
- BEIJING GOLDWIND SCIENCE & CREATION WINDPOWER EQUIPMENT COMPANY CN 536