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 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.

Abstract: A borehole drilling apparatus adapted for connection to a drilling string, wherein the cuttings pass through the center of the drill bit and are adapted for conveyance to the surface through a central pipe of the drilling string, a labyrinth seal being located between the outer perimeter of the apparatus and the wall of the borehole to provide an annular region of relatively immobile or stagnant fluid around the apparatus to forestall movement of fluid upwardly and downwardly past the labyrinth seal, part of the drilling fluid being conducted in a downward direction below the seal to force cuttings toward and through the center of the drill bit for upward conveyance through the central pipe, another portion of the drilling fluid being discharged above the seal for upward conveyance through the annulus between the drilling string and wall of the borehole to the top of the latter, whereby any formation material which may drop into the borehole annulus will be forced upwardly through such annulus to the top of t

Abstract: An airhammer embodies an outer housing structure connectible 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. Upon elevating the airhammer off the bottom of the bore hole being drilled, the anvil bit drops downwardly of the housing structure to open one or more air bleeding grooves in the anvil bit, compressed air in the housing structure bleeding quickly through such grooves and preventing or stopping the hammer piston from reciprocating and impacting against the anvil bit.

Abstract: A dual concentric pipe string for bore hole coring having inner and outer concentric pipe sections, the outer pipe sections being secured together by the usual threaded connection, the inner pipe sections being connected through coupling devices containing elastomeric bodies that make a friction fit with the end portions of adjacent inner pipe sections, the inner pipe sections being frictionally secured to longitudinally spaced elastomeric centralizers having circumferentially spaced longitudinal ribs engaging the inner wall of the outer pipe sections to maintain the inner sections coaxial of the outer sections, with some of the centralizers engaging transverse shoulders in the outer sections to secure the inner sections in the outer sections against substantial longitudinal movement with respect thereto.

Abstract: An air hammer embodying an outer housing structure connectible to a rotatable drill pipe string through which compressed air is conducted. A hammer piston reciprocates in the housing structure along flexible inlet and outlet tubes, 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 piston contacts the housing structure at the upper and lower portions of the piston only, so that the piston can deviate upon flexing of the housing structure under load, and not bind in the housing structure, as permitted by the flexible inlet and outlet tubes.

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.

Abstract: An airhammer and core bit apparatus including a housing and a hammer piston reciprocable in the housing for delivering repeated impact blows to an anvil secured to or forming part of a core bit which produces a core in a bore hole being drilled. A central core receiving tube extends through the housing and hammer piston, through which the core formed by the bit is conducted upwardly and through the hammer piston to the top of the bore hole, part of the compressed air supplied to the airhammer being diverted to the central tube for elevating the core therewithin toward the top of the bore hole.

Abstract: An impact type of anvil core bit includes a body having a central opening through its bottom drilling face, a plurality of spaced cutters, such as sintered tungsten carbide buttons, being secured to the body and extending downwardly from the face to drill against the bottom of the bore hole outwardly of the central opening, the cutters including inner cutters for forming the core in the bottom of the hole, a cutter ring being secured to the body and circumscribing the opening above the bottom of the hole to shape the core for movement into the central opening.