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US 5,511,628 AGranted
Pneumatic drill with central evacuation outlet
OwnerArdis L. Holteinventor
Life of this patent
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OwnerArdis L. Holteinventor
Estimating the term…
A drill bit is mounted for percussive reciprocal movement in the lower end segment of a drill wear tube. A barrel is in the wear tube and defines a first and second series of exhaust ports. Channels in the barrel communicate the exhaust ports with discharge openings spaced about the head of the drill bit. An inlet opening in the face of the drill bit receives airborne earthen particles carried to an evacuation tube. Keys and keyways are disposed about the drill bit in parallel with the drill bit axis permitting a passageway of optimum size. Disposed within the barrel is a tubular piston which reciprocates in response to pressurized air alternately directed to the piston ends. The piston ends open and close the barrel exhaust ports. Internal surfaces of the piston cooperate with surfaces on the evacuation tube and on a press fitted sleeve thereon to direct compressed air to the piston ends.
A pneumatic percussion drill for attachment to a length of drill pipe and including:
In an improved pneumatic percussion drill having a barrel and an elongate drill bit having a shank and an axial passageway with said shank slidably carried by said barrel, the improvement comprising lengthwise disposed keyways defined by and spaced about the drill bit shank, key slots defined by and spaced about said barrel, elongate keys in said keyways and said key slots, said keys in parallel with the major axis of said drill bit and of lesser length than said keyways to permit reciprocal travel of the drill bit.
Dependencies are inferred from the claim text.