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:
Dec. 29, 1981
Filed:
Dec. 10, 1979
Robert F Evans, La Habra, CA (US);
Other;
Abstract
The advancement angle of a borehole cut by a rotary drill bit of the type which forms a cylindrical sidewall, a drill face and a circumferentially extending gage corner, is controlled by removing a different amount of the gage corner material over a selected partial arc of the gage corner circumference during each rotation of the drill bit. The different amount of material removed causes the remaining arc of the gage corner circumference to apply a slight lateral force on the drill bit, thus forcing the drill bit in a desired direction. Gage corner removal apparatus include a hydraulic fluid jet impinging upon the gage corner. Selectively activating the gage corner removal apparatus during each of a plurality of subsequent drill bit revolutions results in a cumulative angle change effect. Control apparatus is attached to the drill string at a position at which gravity induced sag causes the drill string to contact the low side portion of the borehole. The control apparatus is arranged for deriving energy from contact and rotation of the drill string relative to the low side portion. The energy derived activates the gage corner removal apparatus.