Abstract: A swivel, particularly useful in core drilling a bore hole, including a rotor rotatable in a stator, the rotor having a passage through which compressed air is forced to an air operated device for producing cores in the bore hole, and also having a return passage through which the cores conveyed by a portion of the compressed air flow into a core receiving chamber in the stator, a pusher or wiper in the chamber being secured to the rotor to rotate therewith and move around the chamber to shift the cores and core particles toward and into a stator outlet.

Abstract: 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 housing 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 acts against the piston over the full internal cross-sectional area of the housing structure in delivering its impact blow, such compressed air acting downwardly over at least a portion of the piston area during its entire downward stroke, including its latter portion, during which the power or impacting air is being exhausted from the housing structure.