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.

Date of Patent:
Nov. 10, 1998

Filed:

Jun. 21, 1996
Applicant:
Inventors:

Gary Ray Portwood, Kingwood, TX (US);

Gary Edward Garcia, The Woodlands, TX (US);

James Carl Minikus, Spring, TX (US);

Per Ivar Nese, Houston, TX (US);

Dennis Cisneros, Kingwood, TX (US);

Chris Edward Cawthorne, The Woodlands, TX (US);

Assignee:

Smith International, Inc., Houston, TX (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B / ; E21B / ;
U.S. Cl.
CPC ...
175331 ; 175374 ;
Abstract

A rolling cone bit includes a cone cutter having a pair of adjacent rows of cutter elements that are positioned so as to divide the sidewall and bottom hole cutting duty. The wear resistance, hardness and toughness of the cutter elements in the adjacent rows are optimized depending upon the type of cutting the respective rows perform. In most applications, the cutter elements experiencing more sidewall cutting will have cutting surfaces that are more wear resistant or harder than the cutting surfaces of cutter elements in rows experiencing more bottom hole duty. Likewise, the cutter elements exposed to more bottom hole duty will generally be tougher than those experiencing substantial sidewall cutting. The material enhancements include varying the grades of tungsten carbide used in the cutter elements and by selectively employing layers of super abrasives, such as PCD or PCBN. The cutter elements may be either inserts or steel teeth.


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