Patent classifications
E
FIXED CONSTRUCTIONS
Load children
E21
EARTH OR ROCK DRILLING; MINING
Load children
E21D
SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
Load children
E21D1/03
mechanically,; e.g. by loading shovels or loading buckets, scraping devices, conveying screws
Load children Filter patents View analytics View as hierarchy
E21D1/06
with shaft-boring cutters
Filter patents View analytics View as hierarchy