Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
E21B1/00—Percussion drilling
E21B1/12—Percussion drilling with a reciprocating impulse member
E21B1/24—Percussion drilling with a reciprocating impulse member the impulse member being a piston driven directly by fluid pressure
E21B1/30—Percussion drilling with a reciprocating impulse member the impulse member being a piston driven directly by fluid pressure by air, steam or gas pressure
Maschinenspannstock mit mehreren nebeneinander oder hintereinander angeordneten, in der gleichen Richtung wirkenden, durch Pressluft oder Druckfluessier beweglichen Spannbacke