Patent ID: 6637528
Filing Date: 2003-10-28
Classification: E21B,F16C

Abstract:
A bit apparatus including:a) a shaft having an engaging portion; b) a cutter member having cutting teeth axially supported on said shaft for rotation about said shaft; and c) a bearing mechanism interposed between said cutter member and said shaft; wherein: said bearing member comprises at least a radial bearing for bearing a radially directed load and a thrust bearing for bearing an axially directed load; said radial bearing includes a shaft-side split bearing member and a cutter-side split bearing member; said shaft-side split bearing member has an engaged portion for engaging said engaging portion in such a manner that said shaft-side split bearing member co-rotates with said shaft; said shaft-side split bearing member and said cutter-side split bearing member are rotatable relative to each other; and a diamond film on at least one of said shaft-side split bearing member and cutter-side split bearing member and on mutually opposing surfaces of both said shaft-side split bearing member and said cutter-side split bearing member.