DIFF Subgroup
E21C 27/20 Mineral freed by means not involving slitting
Introduced: September 1968
Full Title
Machines which completely free the mineral from the seam > Mineral freed by means not involving slitting
IPC and CPC are identically structured here. All 7 subcodes exist in both systems.
2 shared codes have differing titles between IPC and CPC.
Child Classifications
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- E21C 27/22 by rotary drills with breaking-down means, e.g. wedge-shaped drills IPC+CPC Available in IPC and CPC
- E21C 27/26 by closely adjacent cutter chains acting on the full working face IPC+CPC Available in IPC and CPC
- E21C 27/28 by percussive drills with breaking-down means, e.g. wedge-shaped tools IPC+CPC Available in IPC and CPC
- E21C 27/32 by adjustable or non-adjustable planing means with or without loading arrangements (by percussed planing means E21C27/46) IPC+CPC Available in IPC and CPC
Top Applicants
Top Applicants (IPC)
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
Top Applicants (CPC)
Class E21,2013–2023, worldwide · Source: EPO PATSTAT
- HALLIBURTON ENERGY SERVICES GROUP US 27,652
- SAUDI ARABIAN OIL COMPANY SA 7,755
- PETROCHINA COMPANY 7,025
- BAKER HUGHES US 6,589
- SCHLUMBERGER TECHNOLOGY US 6,151
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 4,443
- SCHLUMBERGER TECHNOLOGY NL 4,255
- CNPC (CHINA NATIONAL PETROLEUM CORPORATION) 3,991
- SERVICES PETROLIERS SCHLUMBERGER FR 3,300
- SCHLUMBERGER CANADA CA 3,086