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U.S. Department of Energy
Office of Scientific and Technical Information

Drill bit having multiple drill rod impact members

Patent ·
OSTI ID:6131422
A drill bit for drilling a subterranean bore hole which includes a housing having a cap plate adapted for connection to a drill pipe and a base block axially aligned with and spaced from the cap plate by guide members. A plurality of elongated drill rod impact members are carried by a drill rod holder plate disposed between the cap plate and base block for movement longitudinally of the housing. The free ends of the drill rods extend through guide bores in the base block to define exposed working ends for chipping and crushing the formation upon rotation of the drill bit and the introduction of drilling fluid into the housing in a manner to effect a hammer-like action of the drill rods and progressively move them longitudinally outwardly from the base block as they undergo wear. Each drill rod is preferably of a cylindrical shape and is made harder at its center axis and progressively softer toward its outer periphery so that the working ends of the drill rods are continually maintained in a generally pointed condition during operation.
Assignee:
EDB-85-043502
Patent Number(s):
US 4478296
OSTI ID:
6131422
Country of Publication:
United States
Language:
English