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, 1987
Filed:
Oct. 14, 1986
Martin A Bollands, Surrey, GB;
William C Pike, Surrey, GB;
Prem S Thukral, Middlesex, GB;
Timothy P Woolmington, Middlesex, GB;
The British Petroleum Company p.l.c., London, GB;
Abstract
A drill shoe adapted to fit onto a drill pipe of external diameter d.sub.e and internal diameter d.sub.i comprises an externally stepped cutting surface comprising a plurality of steps, the diameters of the steps increasing as they progress away from the tip of the shoe. The maximum external diameter D.sub.e of the shoe is greater than the external diameter d.sub.e of the drill pipe. The shoe also comprises an internal, substantially cylindrical, inner surface of diameter D.sub.i, D.sub.i being less than the internal diameter d.sub.i of the drill pipe. The shoe is suitable for use in a vibratory drill string for obtaining cores from unconsolidated geological formations, such as soil, sand and gravel or similar materials.