Patent classifications
E
FIXED CONSTRUCTIONS
Load children
E21
EARTH OR ROCK DRILLING; MINING
Load children
E21B
EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
Load children
E21B1/38
Hammer piston type, i.e. in which the tool bit or anvil is hit by an impulse member
Filter patents View analytics View as hierarchy