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:
Aug. 01, 1989
Filed:
Aug. 15, 1988
Applicant:
Inventor:
Robert N Behrens, Glendale, AZ (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B / ; E21B / ; E21B / ;
U.S. Cl.
CPC ...
175389 ; 175135 ; 175215 ; 175320 ; 175415 ; 175418 ;
Abstract
Drill steel or bit apparatus includes a primary drill bit having a base and a stem, a drill tip, and a bore extending longitudinally through the base, the stem, and the tip, and a pilot drill bit having a base and a stem, and a tip, and the stem and the tip extend through the longitudinal bore in the primary drill bit. The pilot drill bit includes a longitudinally extending bore through which compressed air flows. The base of the pilot drill bit is impacted by a drill piston and the base of the pilot drill bit in turn impacts the primary drill bit. Drilling is accomplished by the tips of both the pilot drill and the primary drill bit.