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. 26, 1989
Filed:
May. 18, 1988
Applicant:
Inventors:
Kurt O Karlsson, Sandviken, SE;
Leif E Karlsson, Karlholmsbruk, SE;
Assignee:
Sandvik AB, Sandviken, SE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B23B / ;
U.S. Cl.
CPC ...
408188 ; 408194 ; 408211 ; 408224 ; 408227 ; 408713 ;
Abstract
A drill for stack drilling comprises a drill body, a central cutting insert, and a peripheral cutting insert. The inserts have active cutting edges arranged such that the drill successively cuts radially outwardly from the center of the drill in order to avoid the formation of break-out slugs. The active cutting edge of the central insert has three cutting edge portions forming obtuse angles with one another. The radially innermost one of those cutting edge portions is shorter than each of the other two cutting edge portions.