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:
Jun. 24, 1997
Filed:
Jan. 09, 1995
Applicant:
Inventor:
Eugene L Foster, Alexandria, VA (US);
Assignee:
UTD Incorporated, Newington, VA (US);
Primary Examiner:
Int. Cl.
CPC ...
E21B / ;
U.S. Cl.
CPC ...
175107 ; 175323 ; 175385 ; 175394 ;
Abstract
A drilling system employs spaced apart cutting members arranged in a helical pattern to form a helical thread within a rock bore. The thread is efficiently fragmented by a wedge-shaped trailing cutting member. Advantageously, a substantial portion of the rock is removed by the fracturing of the internal thread in the rock bore by the uppermost cutting member, taking advantage of the weakness of rock in tension. The rotational speed of the helical cutting system may be controlled as a function of the axial thrust applied to a pilot bit located in front of the helical cutting system.