CPC Main Group
E21D 23/00 Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor ( shifting of mine conveyors at the working face E21F13/08)
Filing statistics
CPC E21D 23/00 belongs to the parent subclass E21D, which recorded 43,973 patent applications worldwide between 2013 and 2023. Annual filings grew from 1,000 in 2013 to 6,074 in 2023 (+507%), peaking at 6,255 applications in 2020. The most active applicants in class E21 are HALLIBURTON ENERGY SERVICES GROUP (27,652 applications), SAUDI ARABIAN OIL COMPANY (7,755 applications) and PETROCHINA COMPANY (7,025 applications).
Source: EPO PATSTAT, worldwide filings
12 direct subcodes
Child Classifications
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- E21D 23/03 having protective means, e.g. shields, for preventing or impeding entry of loose material into the working space or support
- E21D 23/04 Structural features of the supporting construction, e.g. linking members between adjacent frames or sets of props; Means for counteracting lateral sliding on inclined floor (E21D23/14 takes precedence)
- E21D 23/08 Advancing mechanisms (E21D23/16 takes precedence)
- E21D 23/12 Control, e.g. using remote control (E21D23/16 takes precedence)
- E21D 23/16 Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices
Top Applicants
Top 10 applicants by patent filingsfor 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