| 摘要 |
An air hammer embodying an outer housing structure connectable to a rotatable drill pipe string through which compressed air is conducted. A hammer piston reciprocates in the housng structure, compressed air being directed alternately to the upper and lower ends of the piston to effect its reciprocation in the structure, each downward stroke inflicting an impact blow upon the anvil portion of an anvil bit extending upwardly within the lower portion of the housing structure. The compressed air exhausts through a non-metallic elastic synthetic resin sleeve or tube fixed to the anvil and extending slidably into the lower portion of the hammer piston, the sleeve being deflectable laterally in the event of misalignment between the hammer piston and the anvil to prevent fatigue failure of the sleeve.
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