The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 16, 1999
Filed:
Feb. 13, 1997
Applicant:
Inventors:
Assignee:
Tone Corporation, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
E21B / ;
U.S. Cl.
CPC ...
175259 ; 175261 ; 175265 ; 175305 ;
Abstract
Extendable bit teeth are supported by the guide grooves formed on the end face at the point of a bit body in such a manner as to be slidable. The extendable bit teeth slide along the guide grooves in an excavating direction to thereby project from the end face at the point of the bit body. The extendable bit teeth slide in an opposite direction to the excavating direction to project from the outer periphery of the point of the bit body. Since the extendable bit teeth are pressed against the ground during excavation, the extendable bit teeth projects from the outer periphery of the point of the bit body so that the bit gauge can be extended, and most of the excavation hole is excavated by the bit body.