| F | SK | MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING |
| F01 | USK | ENGINES OR PUMPS |
| F01 | KL | MACHINES OR ENGINES IN GENERAL (combustion engines F02; machines for liquids F03 , F04); ENGINE PLANTS IN GENERAL; STEAM ENGINES |
| F02 | KL | COMBUSTION ENGINES (cyclically operating valves therefor, lubricating, exhausting, or silencing engines F01); HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS |
| F03 | KL | MACHINES OR ENGINES FOR LIQUIDS (for liquids and elastic fluids F01; positive-displacement machines for liquids F04); WIND, SPRING, WEIGHT, OR MISCELLANEOUS MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR |
| F04 | KL | POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS (portable fire extinguishers with manually-operated pumps A62C 11/00 , with power-driven pumps A62C 25/00; charging or scavenging combustion engines by pumps F02B; engine fuel-injection pumps F02M; ion pumps H01J 41/12; electrodynamic pumps H02K 44/02) |
| F15 | USK | ENGINEERING IN GENERAL |
| F15 | KL | FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL |
| F16 | KL | ENGINEERING ELEMENTS OR UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL |
| F17 | KL | STORING OR DISTRIBUTING GASES OR LIQUIDS (water supply E03B) |
| F21 | USK | LIGHTING; HEATING |
| F21 | KL | LIGHTING (electric aspects or elements, see section H, e.g. electric light sources H01J , H01K , H05B) |
| F22 | KL | STEAM GENERATION (chemical or physical apparatus for generating gases B01J; chemical generation of gas, e.g. under pressure, Section C; removal of combustion products or residues, e.g. cleaning of the combustion contaminated surfaces of tubes of boilers, F23J; generating combustion products of high pressure or high velocity F23R; water heaters not for steam generation F24H , F28; cleaning of internal or external surfaces of heat-transfer conduits, e.g. water tubes of boilers, F28G) |
| F23 | KL | COMBUSTION APPARATUS; COMBUSTION PROCESSES |
| F24 | KL | HEATING; RANGES; VENTILATING (protecting plants by heating in gardens, orchards, or forests A01G 13/06; baking ovens and apparatus A21B; cooking devices other than ranges A47J; forging B21J , B21K; specially adapted for vehicles, see the relevant subclasses of classes B60 to B64; combustion apparatus in general F23; drying F26B; ovens in general F27; electric heating elements or arrangements H05B) |
| F25 | KL | REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION OR SOLIDIFICATION OF GASES |
| F26 | KL | DRYING |
| F27 | KL | FURNACES; KILNS; OVENS; RETORTS (specially adapted for a purpose covered by a single other class and specifically mentioned in that class, see the class in question, e.g. bakery ovens A21B , glass melting furnaces C03B , coke or gas-making apparatus C10B , C10J , apparatus for cracking hydrocarbons C10G , blast furnaces C21B , converters for making steel C21C , furnaces for heat treatment of metal C21D; furnaces for electroslag or arc remelting of metals C22B 9/00; enamelling ovens C23D; combustion apparatus F23; electric heating H05B) [4] |
| F28 | KL | HEAT EXCHANGE IN GENERAL (heat-transfer, heat-exchange or heat-storage materials C09K 5/00; arrangement or mounting of heat-exchangers in air-conditioning, air-humidification or ventilation F24F 13/30) |
| F41 | USK | WEAPONS; BLASTING |
| F41 | KL | WEAPONS |
| F42 | KL | AMMUNITION; BLASTING |