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:
Sep. 26, 1989
Filed:
Aug. 31, 1988
Naresh J Kar, Westminster, CA (US);
Thomas W Oldham, Mission Viejo, CA (US);
Smith International, Inc., Houston, TX (US);
Abstract
A new and improved tungsten carbide insert for rock bits is disclosed, in which the inserts are subject to extended vibratory tumbling in order to increase their fracture toughness. More specifically the vibratory finishing or tumbling of the inserts has been increased from a typical time of 30-60 minutes to time periods of at least 90 minutes and preferably a minimum of 225 minutes. A marked improvement in toughness is obtained by this process because the size and distribution of surface flaws of the inserts were greatly reduced, and because the surface hardness of the inserts was increased, thereby resulting in an increase in the stress required to cause fracture, and a consequent increase in resistance to breakage.