IPC Subgroup
E21C 47/02 for coal, brown coal, or the like
Introduced: September 1968
Last revised: January 2006
Full Title
Machines for obtaining, or the removal of, materials in open-pit mines > for coal, brown coal, or the like
Classification Context
- Section:
- FIXED CONSTRUCTIONS
- Class:
- EARTH OR ROCK DRILLING; MINING
- Subclass:
- MINING OR QUARRYING
Related Keywords
mining LIGNITE
3 direct subcodes
Child Classifications
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- E21C 47/04 Conveyor bridges used in co-operation with the winning apparatus
- E21C 47/06 Cableway conveyors used in co-operation with the winning apparatus
- E21C 47/08 Devices for cutting-out partings, e.g. layers of sand between seams of coal
Top Applicants
Top 10 applicants by patent filingsfor class E21, 2013–2023, worldwide · Source: EPO PATSTAT
- HALLIBURTON ENERGY SERVICES GROUP US 26,607
- PETROCHINA COMPANY 14,382
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 10,137
- CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 6,517
- BAKER HUGHES US 6,269
- SCHLUMBERGER TECHNOLOGY US 5,929
- SAUDI ARABIAN OIL COMPANY SA 5,880
- SOUTHWEST PETROLEUM UNIVERSITY 4,477
- CHINA UNIVERSITY OF MINING AND TECHNOLOGY 4,357
- SCHLUMBERGER TECHNOLOGY NL 4,219